Basic metal nitrate, process for producing the same and gas generating agent composition

ABSTRACT

A basic metal nitrate suitable as an oxidizing agent for a gas generating agent, which is a basic metal nitrate having a good thermal stability and meeting at least one requirement of the following (a) to (d): (a) a particle diameter of 0.5 to 40 μm; (b) a degree of crystallinity having 0.4 deg or less of a half band width of the peak in the X-ray analysis; (c) an initiation temperature of weight loss being 220° C. or higher according to TG-DTA analysis; and (d) an impurity content of 1,000 ppm or less based on Na atom. Also, a gas generating composition which has a low toxicity, a high burning rate, and a low combustion temperature and which is used in a gas generator for an air bag. The gas generating composition comprises (a) tetrazole derivatives, guanidine derivatives or a mixture thereof, (b) a basic metal nitrate, and (c) a binder and/or a slag-forming agent.

TECHNICAL FIELD TO WHICH THE INVENTION BELONG

The present invention relates to a novel basic metal nitrate, a processfor producing the same, a gas generating composition, its molded articleand a gas generator for an air bag using the gas generating composition.It is suitable for an air bag restraining system of automobiles or thelike.

RELATED ART

As a gas generating agent for an air bag as a passenger-protectingdevice in automobiles, a composition using sodium azide has been oftenused so far. However, a toxicity [LD₅₀ (oral-rat)=27 mg/kg] to humanbodies or hazards in handling of sodium azide has been regarded as aserious problem. Therefore, as safe non-azide based gas generatingcompositions, gas generating compositions containing variousnitrogen-containing organic compounds have been developed to replace theabove conventional composition.

For example, U.S. Pat. No. 4,909,549 discloses a composition comprisinghydrogen-containing tetrazole and triazole compounds and anoxygen-containing oxidizing agent. U.S. Pat. No. 4,370,181 discloses agas generating composition comprising a hydrogen-free bitetrazole metalsalt and an oxygen-free oxidizing agent. U.S. Pat. No. 4,369,079discloses a gas generating composition comprising a hydrogen-freebitetrazole metal salt, an alkali metal nitrate, an alkali metalnitrite, an alkaline earth metal nitrate, an alkaline earth metalnitrite or a mixture thereof. U.S. Pat. No. 5,542,999 discloses a gasgenerating composition comprising a fuel such as GZT, TAGN, NG(nitroguanidine), NTO or the like, a basic copper nitrate, a catalystfor reducing toxic gases and a coolant agent. JP-A 10-72273 discloses agas generating composition comprising a bitetrazole metal salt, abitetrazole ammonium salt or aminotetrazole and ammonium nitrate.

However, the above non-azide based gas generating composition isproblematic in a combustion temperature, a burning rate, phase transfer,amounts of carbon monoxide and nitrogen oxides generated, a gas outputand the like. For example, the gas generating composition of U.S. Pat.No. 4,369,079 has a high combustion temperature, and requires a largeamount of a coolant in actual use. The composition of U.S. Pat. No.5,542,999 has a low burning rate, and might not be completely burned ina short time. In the gas generating agent of JP-A 10-72273, a shape ischanged due to phase transfer of ammonium nitrate in the range of theuse temperature, which damages a molded article of the gas generatingagent, and in result, stable combustion cannot be obtained.

Further, JP-A 9-328389 discloses a gas generating composition comprisinga fuel and an oxidizing agent, 60 to 100% by weight of the fuel beingpolyamine nitrates represented by the formulas (I) to (III) and thebalance of an alkyldiamine having 2 or 3 carbon atoms, and the oxidizingagent being a copper compound. In this related art, effects such as ahigh gas yield and the like are obtained only by using the polyaminenitrates as an essential component of the fuel.

Still further, JP-A 11-343192 discloses a gas generating compositioncomprising a fuel mixture comprising at least two components and anoxidizing agent mixture comprising at least three components, whereinthe fuel mixture contains a guanidine compound and a heterocyclicorganic acid as essential components, and the oxidizing agent mixturecontains a transition metal oxide, a basic copper nitrate and a metalchlorate, a metal perchlorate, ammonium perchlorate, an alkali metalnitrate, an alkaline earth metal nitrate or a mixture thereof asessential components. In this related art, the satifsactory effects inan ignitability and a burning rate are obtained only by the combinationof the fuel mixture of at least two components and the oxidizing agentmixture of at least three components.

Furthermore, U.S. Pat. No. 5,542,998 discloses a gas generating mixturecomprising a fuel, an oxidizing agent and a catalyst, the oxidizingagent being a basic copper nitrate, and the catalyst being a metaloxide. It describes that a coolant agent can be used as an optionalcomponent and a slag-forming agent is unnecessary. U.S. Pat. No.5,542,999 discloses a gas generating mixture comprising a fuel, anoxidizing agent and a catalyst, the oxidizing agent being a basic coppernitrate, and the catalyst being a supported metal or metal alloy. Itdescribes that a coolant agent can be used as an optional component anda slag-forming agent is unnecessary.

Since both of these two related art use the metallic catalyst as anessential component, the production cost is high. In comparison with acatalyst-free gas generating agent, when the same gas output is secured,the weight is increased. Meanwhile, when the weight is decreased, thegas output is decreased. Thus, this is not practical at presentespecially because downsizing of a gas generator is in high demand.

Moreover, FR-C 2,772,370 discloses a pyrotechnic gas generatingcomposition comprising, as essential components, a crosslinked reducingbinder selected from the group consisting of a silicone resin, an epoxyresin and a polyacrylic rubber, an additive comprising a mixture of acopper compound and an organic nitrogen-containing compound and a mainoxidizing agent containing a mixture of ammonium perchlorate and achlorine scavenger. This related art can improve an ignitability and thelike only by such a composition.

In addition, for a non-azide based gas generating agent, physical andchemical interactions are exerted in some combination of a fuel and anoxidizing agent over a long period of time. Consequently, problems arisesuch that a fuel component is gradually decomposed and a thermaldecomposition temperature of the fuel becomes lower than an originallydesigned temperature. When the thermal decomposition temperature of thefuel is thus decreased, the gas generating agent is sometimes degradedduring a long term. Accordingly, a gas generating agent having a highstorage stability with less decomposition of a fuel has been in demand.

DISCLOSURE OF THE INVENTION

A object of the invention is to provide a basic metal nitrate which canprovide a gas generating agent having a high process for producing thesame.

Another object of the invention is to provide a gas generatingcomposition which is high in storage stability before actuation, as wellas in safety at the time of handling, and that has, during actuation, alow combustion temperature, a high burning rate, small amounts of carbonmonoxide and nitrogen oxides formed and good combustion stability.

Still another object of the invention is to provide a gas generator foran air bag using the gas generating composition.

The object of the invention is to provide a gas generating compositionwhich is different in formulation from the compositions of the relatedart, and that has a low combustion temperature, a high burning rate,small amounts of carbon monoxide and nitrogen oxides generated and goodcombustion stability, its molded article and a gas generator for an airbag using the same.

The invention provides basic metal nitrates (BCN) specified below, aprocess specified below, and basic metal nitrates obtained by theprocess. These basic metal nitrates provide gas generating compositionsby being used along with other components of a gas generating agentexemplified in the invention.

The invention provides a gas generating composition comprising a basicmetal nitrate. This composition preferably comprises a basic metalnitrate (BCN) specified below and a basic metal nitrate obtained by aprocess specified below.

The invention provides a basic metal nitrate meeting at least onerequirement of the following (a) to (d):

(a) a particle diameter of 0.5 to 40 μm;

(b) a degree of crystallinity having 0.35 deg or less of a half bandwidth in the peak of the X-ray diffraction;

(c) an initiation temperature of weight loss being 220° C. or higheraccording to TG-DTA analysis; and

(d) an impurity content of 1,000 ppm or less based on Na atom.

The basic metal nitrate of the invention is excellent in thermalstability.

Further, the invention provides a process for producing a basic metalnitrate by reacting a metal nitrate with an alkali metal bicarbonate.

Still further, the invention provides a gas generating compositioncomprising a fuel and a basic metal nitrate, the basic metal nitratemeeting at least one requirement selected from the following (a-1) to(a-3):

(a-1) a particle diameter of 0.5 to 40 μm;

(a-2) a specific surface area of particles being 0.4 to 6.0 m²/g; and

(a-3) a bulk density of particles being 0.4 g/ml or more.

Furthermore, the invention provides a gas generating compositioncomprising a fuel and a basic metal nitrate, the basic metal nitratebeing in the form of secondary particles of coagulated principalparticles, and the secondary particles meeting at least one requirementselected from the following (a-1) to (a-3):

(a-1) a particle diameter of 0.5 to 40 μm;

(a-2) a specific surface area of particles being 0.4 to 6.0 m²/g; and

(a-3) a bulk density of particles being 0.4 g/ml or more.

Moreover, the invention provides an inflator for an air bag using theabove gas generating composition.

Incidentally, the measuring conditions of requirements (a) to (d) and(a-1) to (a-3) are described in Examples.

The basic metal nitrate in the invention includes compounds representedby the following formula. Further, some compounds are hydrates thereof.In the formula, M represents a metal, x′ represents the number ofmetals, y and y′ each represent the number of NO₃ ions, z′ representsthe number of OH ions, and n presents a ratio of an M(OH)_(z) moiety toan M(NO₃)_(y) moiety.M(NO₃)_(y′)nM(OH)_(z) or M_(x′)(NO₃)_(y′)(OH)_(z′)

Examples of the compounds corresponding to the formula include compoundscontaining, as a metal M, copper, cobalt, zinc, manganese, iron,molybdenum, bismuth and cerium, such as Cu₂(NO₃)(OH)₃, Cu₃(NO₃)(OH)₅.2H₂O, Co₂(NO₃)(OH)₃, Zn₂(NO₃)(OH)₃, Mn(NO₃)(OH)₂, Fe₄(NO₃)(OH)₁₁. 2H₂O,Bi(NO₃)(OH)₂and Ce(NO₃)₃(OH).3H₂O.

As the basic metal nitrate, at least one selected from the groupconsisting of a basic copper nitrate (BCN), a basic cobalt nitrate, abasic zinc nitrate, a basic manganese nitrate, a basic iron nitrate, abasic molybdenum nitrate, a basic bismuth nitrate and a basic ceriumnitrate is proposed. Of these, a basic copper nitrate is preferable.

The invention provides, as one means for solution, a gas generatingcomposition comprising (a) at least one guanidine derivative selectedfrom the group consisting of tetrazole derivatives, guanidine, guanidinecarbonate, nitroguanidine, dicyandiamide, nitroaminoguanidine andnitroaminoguanidine nitrate and (b) a basic metal nitrate.

The invention provides, as another means for solution, a gas generatingcomposition comprising (a) at least one guanidine derivative selectedfrom the group consisting of tetrazole derivatives, guanidine, guanidinecarbonate, nitroguanidine, dicyandiamide, nitroaminoguanidine andnitroaminoguanidine nitrate, (b) a basic metal nitrate and (c) a binderand/or a slag-forming agent.

The invention provides, as still another means for solution, a gasgenerating composition comprising (a) tetrazole derivatives, guanidinederivatives or a mixture thereof, (b) a basic metal nitrate and (d) acombustion-improving agent.

The invention provides, as the other means for solution, a gasgenerating composition comprising (a) tetrazole derivatives, guanidinederivatives or a mixture thereof, (b) a basic metal nitrate, (c) abinder and/or a slag-forming agent and (d) a combustion-improving agent.

The invention provides, as the other means for solution, a gasgenerating composition comprising (a) tetrazole derivatives, guanidinederivatives or a mixture thereof and (b) a basic metal nitrate, andmeeting at least one requirement selected from the following (1) to (3):

(1) a weight loss ratio of the gas generating composition when the gasgenerating composition is retained in a closed state at 90° C. for 1,000hours or at 110° C. for 400 hours is 2.0% or less,

(2) concentrations of trace gases contained in a gas generated by thecombustion of the gas generating composition, as values measured in a2,800-liter tank, 400 ppm or less for CO, 40 ppm or less for NO, 8 ppmor less for NO₂ and 100 ppm or less for NH₃, and

(3) a maximum internal pressure in a gas generator on the combustion ofthe gas generating composition is 7,840 to 22,500 kPa.

Further, the invention provides a gas generating composition comprising(a) tetrazole derivatives, guanidine derivatives or a mixture thereof,(b) a basic metal nitrate and (c) a binder and/or a slag-forming agent,and meeting at least one requirement of the following (1) to (3):

(1) a weight loss ratio of the gas generating composition when the gasgenerating composition is retained in a closed state at 90° C. for 1,000hours or at 110° C. for 400 hours is 2.0% or less,

(2) concentrations of trace gases contained in a gas generated by thecombustion of the gas generating composition, as values measured in a2,800-liter tank, 400 ppm or less for CO, 40 ppm or less for NO, 8 ppmor less for NO₂ and 100 ppm or less for NH₃, and

(3) a maximum internal pressure in a gas generator on the combustion ofthe gas generating composition is 7,840 to 22,500 kPa.

Still further, the invention provides a molded article in the form of asingle-perforated cylinder, a perforated (porous) cylinder or pellets,the molded article being obtained from the gas generating composition.

Furthermore, the invention provides an inflator for an air bag using thegas generating composition and the molded article. By the way, the“inflator” in the invention means a pyrotechnic inflator in which a gasis supplied only from a gas generating agent and a hybrid inflator inwhich a gas is supplied from both a compressed gas such as argon or thelike and a gas generating agent (provided a portion having a function togenerate a gas by burning the gas generating agent is a “gasgenerator”).

The basic metal nitrate of the invention has a high thermal stability.Accordingly, even when the basic metal nitrate is allowed to stand in ahigh-temperature atmosphere for a long period of time (for example, tento ten-odd years) degeneration such as decomposition or the like doesnot occur. Therefore, it is suitable as an oxidizing agent of a gasgenerating agent used in an air bag inflator as a safety device ofautomobiles in particular, or the like.

The basic metal nitrate of the invention suppresses physical andchemical interactions in combination with a fuel component, especiallyguanidine derivatives such as nitroguanidine and the like, making itpossible to prevent the decrease in thermal stability by the decrease indecomposition temperature of the fuel component.

The process of the invention can industrially produce a basic metalnitrate such as a basic copper nitrate or the like under easilycontrollable reaction conditions using starting materials less costlyand easily available industrially without the need of a special reactionequipment.

When the gas generating composition of the invention is used in variousinflators, a high reliability can be maintained for a long period oftime because of the excellent thermal stability.

The gas generating composition and its molded article of the inventionare easy to handle because they have a low toxicity and are lessdangerous. Further, they have a high burning rate and a low combustiontemperature, and the amounts of carbon monoxide and nitrogen oxidesgenerated in the combustion are small.

Embodiment 1 of the Invention

The basic metal nitrate having the good thermal stability in theinvention meets at least one requirement of the following (a) to (d). Itmeets preferably at least one requirement and as many requirements aspossible, and most preferably all of the requirements. Further, when atleast two requirements are met, it is preferable that at leastrequirement (a) is met.

requirement (a): a particle diameter being 0.5 to 40 μm, preferably 0.5to 20 μm, more preferably 1 to 10 μm; it may be 2 to 40 μm or 2 to 20μm;

requirement (b): a degree of crystallinity having 0.35 deg or less of ahalf band width, preferably 0.26 deg or less of the peak in the X-raydiffraction;

requirement (c): an initiation temperature of weight loss being 220° C.or higher, preferably 215° C. or higher according to TG-DTA analysis;and

requirement (d): an impurity content of 1,000 ppm or less, preferably600 ppm or less based on Na atom. The basic metal nitrate of thisembodiment is excellent in thermal stability.

The process for producing the basic metal nitrate is described below.The basic metal nitrate of the invention can be produced, for example,by reacting a metal nitrate with an alkali metal bicarbonate. Thereaction procedure is represented by the following reaction scheme (II)in a case of the basic copper nitrate.4Cu(NO₃)₂.3H₂O+6MHCO₃→Cu(NO₃)₂.3Cu(OH)₂+6MNO₃+6CO₂+12H₂O   (II)

wherein M is an alkali metal.

As is clear from this reaction scheme (II), by selecting an alkali metalbicarbonate as a basic weak acid salt, the alkali metal bicarbonate isreacted with a metal nitrate, and an alkali metal ion is bound to anitrate group to form an alkali metal nitrate that is well soluble inwater. A bicarbonate anion is reacted with a hydrogen ion to form acarbon dioxide gas and water.

Thus, according to the process of the invention represented by reactionscheme (II), a nitrate formed is neutralized with a basic weak acidsalt, and the neutralized weak acid is escaped from the solution as agas because it is unstable. Accordingly, the formation of the basicmetal nitrate is not interrupted.

As the process for producing the basic metal nitrate of the invention,the process in which the metal nitrate is reacted with the alkali metalbicarbonate is preferable. A process using a strong basic material suchas an alkali metal hydroxide compound or an alkali metal carbonate (forexample, potassium hydroxide or sodium carbonate) is also available. Bythe way, when the strong basic material is used, byproducts are formedby side reactions as shown by reaction schemes (III), (IV) and (V). Thepresence of such byproducts is considered to decrease the thermalstability.2KOH+Cu(NO₃)₂→Cu(OH)₂+2KNO₃   (III)Cu(NO₃)₂.3Cu(OH)₂+2KOH→4CuO+4H₂O+2KNO₃   (IV)Cu(NO₃)₂.3Cu(OH)₂+2Na₂CO₃→2Cu₂O₃(OH)₂+2NaOH+2NaNO₃   (V)

Examples of the metal nitrate include cobalt nitrate, copper nitrate,zinc nitrate, manganese nitrate, iron nitrate, molybdenum nitrate,bismuth nitrate, cerium nitrate and the like of these, copper nitrate ispreferable. As copper nitrate, compounds represented by the followingformula (I) are preferable, and copper nitrate 3-hydrate and coppernitrate 6-hydrate are more preferable. Such copper nitrate compounds arecommercially available, and can be procured at low costs.Cu(NO₃)₂.nH₂O   (I)

wherein n is 0 to 6.

The metal nitrate such as copper nitrate or the like can be used in theform of an aqueous solution or by being dissolved in a mixed solvent ofa water-soluble organic solvent (for example, ethanol) and water.Generally, it is used in the form of an aqueous solution.

The concentration of the metal nitrate such as copper nitrate or thelike in the solution is not particularly limited, and it can optionallybe selected from a concentration of a 1% solution to a concentration ofa saturated solution. Generally, it is preferable that the amount of thesolvent is 200 to 5,000 ml per one mol of the metal nitrate such ascopper nitrate or the like. When the concentration is higher than thisrange, the crystallization of the resulting basic metal nitrate such asa basic copper nitrate or the like tends to be worsened, and the thermalstability becomes poor. Incidentally, although excess solvent is used,the effect corresponding to the amount is not obtained, and treatmentsuch as recovery or the like of alkali metal nitrates as byproductstakes much time. Thus, it is unwanted.

Examples of the alkali metal bicarbonate that neutralizes the metalnitrate such as copper nitrate or the like can include sodiumbicarbonate, potassium bicarbonate, lithium bicarbonate, rubidiumbicarbonate and cesium bicarbonate. Sodium bicarbonate and potassiumbicarbonate are preferable from the economical aspect. Such alkali metalbicarbonates are mass-produced industrial agents, and industrialstarting materials which are less costly and easily industriallyavailable.

The alkali metal bicarbonate can be used in the form of a solid or asolution. As the solvent in the form of a solution, water or a mixedsolvent of a water-soluble organic solvent (for example, ethanol) andwater can be used. Generally, the alkali metal bicarbonate is used inthe form of an aqueous solution.

The amount of the solvent is preferably about 1 to 10 liters per one molof the alkali metal bicarbonate. When the alkali metal bicarbonate isused in the form of a solid or at a concentration higher than theabove-described range, it is required to have some device, such as todecrease the concentration of nitric acid in the solution of the metalnitrate such as copper nitrate or the like. Otherwise, the alkaliconcentration is, in some cases, locally increased when it is added tothe solution of the metal nitrate such as copper nitrate or the like,which induces formation of copper hydroxide as a side reaction and makesit impossible to form the basic metal nitrate such as a basic coppernitrate or the like having a good thermal stability with a goodreproducibility.

The mixing ratio of the metal nitrate such as copper nitrate or the likeand the alkali metal bicarbonate is that the amount of the alkali metalbicarbonate is preferably 2 mols or less, more preferably 1.0 to 1.7mols per one mol of the metal nitrate such as copper nitrate or thelike. When the amount of the alkali metal bicarbonate is less than thisrange, the quality of the basic metal nitrate such as a basic coppernitrate or the like is not improved, and a yield of the basic metalnitrate such as a basic copper nitrate or the like is decreased. Thus,it is meaningless in view of an industrial process. Further, when theamount is larger than this range, it is unwanted because a metalhydroxide such as copper hydroxide or the like is incorporated into thebasic metal nitrate such as a basic copper nitrate or the like.

A method for mixing the metal nitrate such as copper nitrate or the likewith the alkali metal bicarbonate is not particularly limited.Generally, it is advisable that a solution of the alkali metalbicarbonate is added to a solution of the metal nitrate such as coppernitrate or the like. Besides, a method can also be employed in which themetal nitrate such as copper nitrate or the like and the alkali metalbicarbonate are added almost simultaneously to a solution of which thepH is previously adjusted to a fixed value. In the addition, it isadvisable to take such measures that these are mixed with stirring inorder to avoid a local increase in the alkali concentration, one or moreaddition ports are provided, and so forth. Since the addition speed isinfluenced by a reaction scale, an extent of stirring, a concentrationof an aqueous solution, the number of addition ports, a mixingtemperature and the like, it has to be determined in consideration ofthese matters. Generally, it is advisable that they are gently added tocontrol the local alkali concentration.

The temperature at which to mix the metal nitrate such as copper nitrateor the like with the alkali metal bicarbonate is not particularlylimited. Generally, the mixing is conducted in the range of roomtemperature to 100° C. It is preferably conducted by heating.

An aging time after the completion of the addition is influenced by amixing temperature, a mixing time and the like, and it cannot absolutelybe determined. However, it is advisable that when the mixing temperatureis high, the aging time is shortened. When the aging time is longer thanas required, a part of the resulting basic metal nitrate such as a basiccopper nitrate or the like is decomposed, and the thermal stability ispoor. Further, when the aging time is shorter, the basic metal nitratesuch as a basic copper nitrate or the like is not satisfactorilycrystallized, and the thermal stability is poor. Thus, it is advisableto determine the aging time in consideration of these influences.

The reaction can also be conducted under the following reactionconditions other than the foregoing reaction conditions. The amount ofthe solvent is 20 to 400 ml, preferably 50 to 200 ml per one mol of themetal nitrate such as copper nitrate or the like. The amount of thesolvent is 0.2 to 2.5 liters, preferably 0.5 to 1.5 liters per one molof the alkali metal bicarbonate. The reaction temperature is 0 to 35°C., preferably 5 to 20° C.

The gas generating composition of the invention is described below. Thegas generating composition of the invention comprises a fuel and a basicmetal nitrate, and further, as required, an additive.

One embodiment of the basic metal nitrate used in the gas generatingcomposition of the invention is that it meets at least one requirementselected from the following (a-1) to (a-3), preferably any tworequirements, more preferably three requirements:

requirement (a-1): a particle diameter of 0.5 to 40 μm, preferably 0.5to 20 μm, more preferably 1 to 10 μm;

requirement (a-2): a specific surface area of particles being 0.4 to 6.0m²/g, preferably 0.5 to 4.0 m²/g, more preferably 0.5 to 2.5 m²/g; and

requirement (a-3): a bulk density of particles being 0.4 g/ml or more,preferably 0.4 to 1.0 g/ml, more preferably 0.7 to 1.0 g/ml.

By meeting requirements (a-1) to (a-3), the following excellent effectsare provided when producing a gas generating composition comprising acompound of which the stability is decreased in combination with a basicmetal nitrate, for example, guanidine derivatives (for example,nitroguanidine) and a basic metal nitrate (for example, a basic coppernitrate) for the following reasons and the like. By the way, the case ofusing nitroguanidine and a basic copper nitrate providing great effectsin particular is described below. However, the gas generatingcomposition of the invention is not limited to this combination.

When nitroguanidine (NQ) is mixed with a basic copper nitrate (BCN) andthe physical and chemical interactions between NQ and BCN are great, thedecomposition temperature of NQ and BCN is decreased, which has anadverse effect on the performance of the gas generating composition.That is, an interaction (for example, the hydrogen bond or the van derWaals force) occurs between —NH₂ of NQ and —OH of BCN. At a hightemperature or the like, water or the like is generated by a chemicalreaction such as dehydration or the like to exert an adverse effect onthe performance of the gas generating composition. However, whenrequirements (a-1) to (a-3) are met, the following functional effectsare provided, and the adverse effect on the performance of the gasgenerating composition is prevented.

Functional Effect Provided by Requirement (a-1)

When the particle diameter of BCN is too small, a large amount of BCN isadhered to the surface of NQ or the like to increase the interactiontherebetween, and there occur influences such as a decrease indecomposition temperature and the like. Accordingly, the particlediameter is limited to the range of requirement (a-1), whereby theinteraction can be decreased to prevent occurrence of the decrease indecomposition temperature and the like.

Functional Effect Provided by Requirement (a-2)

When the specific surface area of BCN is large, the total surface areaof BCN is, in comparison with the use of BCN having a small specificsurface area, increased even with the same amount of BCN, so that theinteraction between NQ and BCN is increased. Accordingly, the specificsurface area is limited to the range of requirement (a-2), whereby theinteraction can be decreased to prevent occurrence of the decrease inthermal decomposition temperature and the like.

Functional Effect Provided by Requirement (a-3)

When the bulk density of BCN is low, the volume per unit weight isincreased, and the specific surface area is increased. Accordingly,requirement (a-2) is not met. Further, in case of coagulated particles,when BCN is cracked during the production of the gas generatingcomposition, since the interaction between a fresh cracked surfacegenerated at that time and NQ is great, firmly coagulated particleswhich have the high bulk density can reduce the interaction to preventthe occurrence of the decrease in decomposition temperature and thelike.

The other embodiment of the basic metal nitrate used in the gasgenerating composition of the invention further meets at least onerequirement selected from (b) to (d), preferably any two requirements,more preferably three requirements in addition to (a-1) to (a-3):

requirement (b): a degree of crystallinity having 0.35 deg or less of ahalf band width, preferably 0.26 deg or less in the peak of the X-raydiffraction;

requirement (c): an initiation temperature of weight loss being 220° C.or higher, preferably 215° C. or higher according to TG-DTA analysis;and

requirement (d): an impurity content of 1,000 ppm or less, preferably600 ppm or less based on Na atom.

By meeting requirements (b) and (c), the stability of the basic coppernitrate itself can be improved. Further, by meeting requirement (d), thestability in case of the combination of nitroguanidine and the basiccopper nitrate can be increased. Still further, by meeting requirements(b) to (d), the effect of controlling the interaction betweennitroguanidine and the basic copper nitrate can be increased more.

The other embodiment of the basic metal nitrate used in the gasgenerating composition of the invention is that the basic metal nitrateis in the form of secondary particles of coagulated principal particles,the secondary particles meeting at least one requirement selected fromthe following (a-1) to (a-3), preferably any two requirements, morepreferably three requirements:

requirement (a-1): a particle diameter of 0.5 to 40 μm, preferably 0.5to 20 μm, more preferably 1 to 10 μm;

requirement (a-2): a specific surface area of particles being 0.4 to 6.0m²/g, preferably 0.5 to 4.0 m²/g, more preferably 0.5 to 2.5 m²/g; and

requirement (a-3): a bulk density of particles being 0.4 g/ml or more,preferably 0.4 to 1.0 g/ml, more preferably 0.7 to 1.0 g/ml.

By meeting requirements (a-1) to (a-3), the above-mentioned effects canbe obtained.

Another embodiment, when the basic metal nitrate used in the gasgenerating composition of the invention is in the form of coagulatedparticles, further meets at least one requirement selected from (b) to(d), preferably any two requirements, more preferably three requirementsin addition to (a-1) to (a-3):

requirement (b): a degree of crystallinity having 0.35 deg or less of ahalf band width, preferably 0.26 deg or less in the peak of the X-raydiffraction;

requirement (c): an initiation temperature of weight loss being 220° C.or higher, preferably 215° C. or higher according to TG-DTA analysis;and

requirement (d): an impurity content of 1,000 ppm or less, preferably600 ppm or less based on Na atom.

By meeting requirements (b) to (d), the above-described effects can beobtained.

This basic metal nitrate in the form of secondary particles ofcoagulated principal particles is preferably formed by coagulating alarge number of principal particles having the form of needles to platesand/or spheres to similar shapes thereto. The “form of needles toplates” means only particles having the form of needles, only particleshaving the form of plates and a mixture of particles having the form ofneedles and particles having the form of plates with a width graduallyincreased from the width of particles having the form of needles. The“form of spheres to similar shapes thereto” means only sphericalparticles, only particles having the form of similar shapes thereto, forexample, particles having concavo-convex portions on the sphericalsurface or oval particles, and a mixture of spherical particles andparticles having the form of similar shapes thereto such as an ovalshape and the like.

The basic metal nitrate formed from the secondary particles is obtainedby laminating and coagulating, for example, a large number of principalparticles having the form of needles to plates. Principal particlesradially arranged in the lowermost layer and laminated radiallyunidirectionally in order, for example, principal particles having theform of needles to plates and laminated in the “chrysanthemum shape” areproposed.

The basic metal nitrate formed from the secondary particles ofcoagulated principal particles is obtained by changing theconcentrations of the metal nitrate and the alkali metal bicarbonate,the reaction temperature and the aging time in the process for producingthe basic metal nitrate.

The amount of the solvent is preferably 20 to 400 ml, more preferably 50to 200 ml per one mol of the metal nitrate such as copper nitrate or thelike (based on anhydride). The amount of the solvent is preferably 0.2to 2.5 liters, more preferably 0.5 to 1.5 liters per one mol of thealkali metal bicarbonate.

The reaction temperature is preferably 10 to 35° C., more preferablyapproximately room temperature. The aging time is preferably set to belonger than in the heating.

The fuel contained in the gas generating composition of the invention isselected from the group consisting of guanidine derivatives, azolederivatives, triazine derivatives and transition metal complexes.

As the guanidine derivatives, at least one selected from the groupconsisting of guanidine, mono-, di- or tri-aminoguanidine nitrate,guanidine nitrate, guanidine carbonate, nitroguanidine (NQ),dicyandiamide (DCDA) and nitroaminoguanidine nitrate is proposed ofthese, nitroguanidine and dicyandiamide are preferable.

As the azole derivatives, at least one selected from the groupconsisting of tetrazole, 5-aminotetrazole, 5.5′-bi-1H-tetrazole,5-nitroaminotetrazole, zinc salt of 5-aminotetrazole, copper salt of5-aminotetrazole, bitetrazole, potassium salt of bitetrazole (BHTK),sodium salt of bitetrazole, magnesium salt of bitetrazole, calcium saltof bitetrazole, diammonium salt of bitetrazole (BHTNH₃), copper salt ofbitetrazole and melamine salt of bitetrazole. Of these, diammonium saltof bitetrazole is preferable because the content of the nitrogen atom is81.4% by weight, LD₅₀ (oral-rat) is 2,000 mg/kg and the combustionefficiency is good. The bitetrazole compounds here refer to include 5-5′compounds and 1-5′ compounds having two tetrazole rings, and 5-5′compounds are preferable because of the cost and the easy procurement.

As the triazine derivatives, at least one selected from the groupconsisting of melamine, trimethylolmelamine, alkylated methylolmelamine,ammeline, ammeland, cyanuric acid, melam, melem, melamine nitrate,melamine perchlorate, trihydrazinotriazine and a nitro compound ofmelamine is proposed. Of these, melamine and trihydrazinotriazine (THT)are preferable because LD₅₀ (oral-rat) is 3,161 mg/kg, the thermalstability is high, the safety is secured in handling and the cost islow.

Of these compounds of the fuel, nitroguanidine is especially preferablebecause the physical and chemical interactions can be decreased when itis used in combination with the basic metal nitrate.

The content of the fuel in the gas generating composition varies withthe type of the oxidizing agent and the oxygen balance. It is preferably10 to60% by weight, more preferably 20 to 50% by weight.

The content of the basic metal nitrate in the gas generating compositionis preferably 40 to 90% by weight, more preferably 50 to 80% by weight.

The gas generating composition can further contain an additives such asa binder, a slag-forming agent and the like. As the binder, at least oneselected from the group consisting of carboxymethylcellulose (CMC),sodium salt of carboxymethylcellulose (CMCNa), potassium salt ofcarboxymethylcellulose, ammonium salt of carboxymethylcellulose,cellulose acetate, cellulose acetatebutylate (CAB), methyl cellulose(MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC),ethylhydroxyethyl cellulose (EHEC), hydroxypropyl cellulose (HPC),carboxymethylethyl cellulose (CMEC), fine crystalline cellulose,polyacrylic amide, amine products of polyacrylic amide, polyacrylichydrazide, a copolymer of an acrylic amide and a metal salt of acrylicacid, a copolymer of polyacrylic amide and polyacrylic ester, polyvinylalcohol, acrylic rubber, guar gum, starch, silicone, molybdenumdisulfide, Japanese acid clay, talc, bentonite, diatomaceous earth,kaolin, calcium stearate, silica, alumina, sodium silicate, siliconnitrate, silicon carbide, hydrotalcite, mica, a metal oxide, a metalhydroxide, a metal carbonate, a basic metal carbonate and a molybdate isproposed. Of these, guar gum is preferable in consideration of thecombination of the fuel and the basic metal nitrate.

As a metal hydroxide, at least one selected from the group consisting ofcobalt hydroxide and aluminum hydroxide is proposed. As a metalcarbonate and a basic metal carbonate, at least one selected from thegroup consisting of calcium carbonate, cobalt carbonate, a basic zinccarbonate, a basic copper carbonate, a basic cobalt carbonate, a basiciron carbonate, a basic bismuth carbonate and a basic magnesiumcarbonate is proposed. As a molybdate, at least one selected from thegroup consisting of cobalt molybdate and ammonium molybdate is proposed.

The content of the additives such as the binder and the like in the gasgenerating composition is preferably 0.1 to 15% by weight, morepreferably 0.5 to 12% by weight.

As the gas generating composition of the invention, it is preferablethat when the gas generating composition (containing 40 g of the gasgenerating agent) is maintained in a closed state, specifically, it ischarged into a stainless steel container having an inner capacity of118.8 ml and maintained in a closed state at 110° C. for 400 hours, theweight loss ratio of the gas generating agent is 2.0% or less,preferably 1.0% or less, more preferably 0.5% or less.

The gas generating composition of the invention can be molded in adesired shape, and formed into a molded article in the shape of asingle-perforated cylinder, a perforated (porous) cylinder or pellets.These molded articles can be produced by a method in which the gasgenerating composition is mixed with water or an organic solvent and themixture is extrusion-molded (molded articles in the form of asingle-perforated cylinder and a perforated (porous) cylinder) or by acompression-molding method using a pelletizer (molded article in theform of pellets).

The gas generating composition of the invention can be used in, forexample, an inflator for an air bag of a driver side, an inflator for anair bag of a passenger side, an inflator for a side air bag, an inflatorfor an inflatable curtain, an inflator for a knee bolster, an inflatorfor an inflatable seat belt, an inflator for a tubular system and a gasgenerator for a pretensioner in various vehicles.

Further, the inflator using the gas generating composition of theinvention may be a pyrotechnic type in which a gas is supplied only froma gas generating agent alone or a hybrid type in which a gas is suppliedfrom both of a compressed gas such as argon or the like and a gasgenerating agent.

Moreover, the gas generating composition of the invention can also beused as an igniting agent called an enhancer (or a booster) fortransferring energy of a detonator or a squib to a gas generating agent.

Embodiment 2 of the Invention

The gas generating composition of the invention can be a compositioncomprising components (a) and (b) as essential components or acomposition comprising components (a), (b) and (c) as essentialcomponents.

Tetrazole derivatives as component (a) used in the invention arepreferable because the content of a nitrogen atom in a molecule is high,the toxicity is low and the burning rate is increased in combinationwith component (b).

Examples of the tetrazole derivatives include tetrazole compounds(except for bitetrazole compounds) and bitetrazole compounds. As thetetrazole compounds (except for bitetrazole compounds), at least oneselected from the group consisting of tetrazole, 5-aminotetrazole,5,5′-bi-1H-tetrazole, 5-nitroaminotetrazole, zinc salt of5-aminotetrazole and copper salt of 5-aminotetrazole is proposed. As thebitetrazole compounds, at least one selected from the group consistingof bitetrazole, potassium salt of bitetrazole (BHTK), sodium salt ofbitetrazole, magnesium salt of bitetrazole, calcium salt of bitetrazole,diammonium salt of bitetrazole (BHTNH₃), copper salt of bitetrazole andmelamine salt of bitetrazole is proposed.

Of these, diammonium bitetrazole is preferable because the content ofthe nitrogen atom is 81.4% by weight, LD₅₀ (oral-rat) is 2,000 mg/kg andthe combustion efficiency is good. The bitetrazole compounds herereferred to include 5-5′ compounds and 1-5′ compounds having twotetrazole rings, and 5-5′ compounds are preferable because of the costand the easy procurement.

In component (a) used in the invention, the guanidine derivatives can bedivided into two groups in view of the combination with other componentsand predetermined requirements (1) to (3) to be met.

The first group is at least one guanidine derivative selected from thegroup consisting of guanidine, guanidine carbonate, nitroguanidine,dicyandiamide, nitroaminoguanidine and nitroaminoguanidine nitrate.

The second group is at least one guanidine derivative selected from thegroup consisting of guanidine, mono-, di- or tri-aminoguanidine nitrate,guanidine nitrate, guanidine carbonate, nitroguanidine (NQ),dicyandiamide (DCDA), nitroaminoguanidine and nitroaminoguanidinenitrate.

The guanidine derivatives as component (a) when the gas generatingcomposition of the invention is the composition comprising components(a) and (b) as essential components or the composition comprisingcomponents (a), (b) and (c) as essential components are the guanidinederivatives of the first group.

The basic metal nitrate as component (b) used in the invention generallyincludes components represented by the following formula. Further, somecompounds are hydrates thereof. In the formula, M represents a metal, x′represents the number of metals, y and y′ each represent the number ofNO₃ ions, z′ represents the number of OH ions, and n represents a ratioof an M(OH)_(z) moiety to an M(NO₃)_(y) moiety.M(NO₃)_(y′)nM(OH)_(z) or M_(x′)(NO₃)_(y′)(OH)_(z′)

Examples of the compounds corresponding to the formula include compoundscontaining, as a metal M, copper, cobalt, zinc, manganese, iron,molybdenum, bismuth and cerium, such as Cu₂(NO₃)(OH)₃,Cu₃(NO₃)(OH)₅.2H₂O, Co₂(NO₃)(OH)₃, Zn₂(NO₃)(OH)₃, Mn(NO₃)(OH)₂,Fe₄(NO₃)(OH)₁₁.2H₂O, Bi(NO₃)(OH)₂ and Ce(NO₃)₃(OH).3H₂O.

As the basic metal nitrate being component (b), at least one selectedfrom the group consisting of a basic copper nitrate (BCN), a basiccobalt nitrate, a basic zinc nitrate, a basic manganese nitrate, a basiciron nitrate, a basic molybdenum nitrate, a basic bismuth nitrate and abasic cerium nitrate is proposed. Of these, a basic copper nitrate ispreferable.

The basic copper nitrate is excellent in thermal stability, as comparedwith ammonium nitrate as an oxidizing agent, because no phase transferoccurs in the range of the use temperature and the melting point ishigh. Further, since the basic copper nitrate acts to lower a combustiontemperature of a gas generating agent, amounts of generated nitrogenoxides can be decreased.

Component (b) can be a mixture of the basic metal nitrate and at leastone other oxidizing agent. In case of the mixture, an alkali metalnitrate can be incorporated as the other oxidizing agent.

The alkali metal nitrate is a component to increase the burning rate ofthe gas generating composition, and examples thereof include potassiumnitrate, sodium nitrate, potassium perchlorate, lithium nitrate and thelike. Of these, potassium nitrate is preferable.

When component (b) is the mixture, the content of the basic metalnitrate in the mixture is preferably 55 to 99.9% by weight, morepreferably 75 to 99.5% by weight, further preferably 90 to 99.2% byweight.

When the gas generating composition of the invention contains components(a) and (b), the content of component (a) is preferably 5 to 60% byweight, more preferably 15 to 55% by weight. The content of component(b) is preferably 40 to 95% by weight, more preferably 45 to 85% byweight.

A preferable example of the composition comprising components (a) and(b) is a composition comprising (a) diammonium salt of bitetrazole and(b) a basic copper nitrate. In this case, the content of (a) ammoniumsalt of bitetrazole is 5 to 60% by weight, preferably 15 to 55% byweight, more preferably 15 to 45% by weight or 15 to 35% by weight, andthecontentof (b) abasiccoppernitrate is 40 to95% by weight, preferably45 to 85% by weight, more preferably 55 to 85% by weight or 65 to 85% byweight.

Another preferable example of the composition comprising components (a)and (b) is a composition comprising (a) nitroguanidine and (b) a basiccopper nitrate. In this case, the content of (a) nitroguanidine is 30 to70% by weight, preferably 40 to 60% by weight. The content of (b) abasic copper nitrate is 30 to 70% by weight, preferably 40 to 60% byweight.

Still another preferable example of the composition comprisingcomponents (a) and (b) is a composition comprising (a) dicyandiamide and(b) a basic copper nitrate. In this case, it is preferable that thecontent of (a) dicyandiamide is 15 to 30% by weight and the content of(b) a basic copper nitrate is 70 to 85% by weight.

The binder and/or the slag-forming agent as component (c) used in theinvention is not crosslinkable. At least one selected from the groupconsisting of carboxymethylcellulose (CMC), sodium salt ofcarboxymethylcellulose (CMCNa), potassium salt ofcarboxymethylcellulose, ammonium salt of carboxymethylcellulose,cellulose acetate, cellulose acetatebutylate (CAB), methyl cellulose(MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC),ethylhydroxyethyl cellulose (EHEC), hydroxypropyl cellulose (HPC),carboxymethylethyl cellulose (CMEC), fine crystalline cellulose,polyacrylic amide, amine products of polyacrylic amide, polyacrylichydrazide, a copolymer of an acrylic amide and a metal salt of acrylicacid, a copolymer of polyacrylic amide and polyacrylic ester, polyvinylalcohol, acrylic rubber, polysaccharides including guar gum and starch,silicone (except for a silicone resin), molybdenum disulfide, Japaneseacid clay, talc, bentonite, diatomaceous earth, kaolin, calciumstearate, silica, alumina, sodium silicate, silicon nitrate, siliconcarbide, hydrotalcite, mica, a metal oxide, a metal hydroxide, a metalcarbonate, a basic metal carbonate and a molybdate is proposed.

Polysaccharides including guar gum or starch as component (c) are notparticularly limited so long as they are sticky and can be applied to awet-molding method and a dry-molding method. Examples thereof includevarious gums such as gum arabic except for guar gum, tragacanth gum andthe like, chitin, chitosan, hyaluronic acid and the like.

As a metal oxide being component (c), at least one selected from thegroup consisting of copper oxide, iron oxide, zinc oxide, cobalt oxide,manganese oxide, molybdenum oxide, nickel oxide and bismuth oxide isproposed. As a metal hydroxide, at least one selected from the groupconsisting of cobalt hydroxide and aluminum hydroxide is proposed. As ametal carbonate and a basic metal carbonate, at least one selected fromthe group consisting of calcium carbonate, cobalt carbonate, a basiczinc carbonate, a basic copper carbonate, a basic cobalt carbonate, abasic iron carbonate, a basic bismuth carbonate and a basic magnesiumcarbonate is proposed. As a molybdate, at least one selected from thegroup consisting of cobalt molybdate and ammonium molybdate is proposed.These compounds as component (c) can act as the slag-forming agentand/or the binder.

For increasing the ignitability of the gas generating composition,sodium salt of carboxymethylcellulose and potassiumcarboxymethylcellulose are preferable. Of these, sodiumcarboxymethylcellulose is more preferable.

When the gas generating composition of the invention comprisescomponents (a), (b) and (c), the content of component (a) is preferably5 to 60% by weight, more preferably 15 to 55% by weight. The content ofcomponent (b) is preferably 40 to 95% by weight, more preferably 45 to85% by weight. The content of component (c) is preferably 0.1 to 25% byweight, more preferably 0.1 to 15% by weight, further preferably 0.1 to10% by weight.

A preferable example of the composition comprising components (a), (b)and (c) is a composition comprising (a) diammonium salt of bitetrazole,(b) a basic copper nitrate and (c) sodium salt ofcarboxymethylcellulose. In this case, it is preferable that the contentof (a) diammonium salt of bitetrazole is 15 to 40% by weight, thecontent of (b) a basic copper nitrate is 45 to 80% by weight and thecontent of (c) sodium carboxymethylcellulose is 0.1 to 15% by weight.

Another preferable example of the composition comprising components (a),(b) and (c) is a composition comprising (a) diammonium salt ofbitetrazole, (b) a basic copper nitrate, (c-1) sodium salt ofcarboxymethylcellulose and (c-2) component (c) except for (c-1). In thiscase, it is preferable that the content of (a) diammonium salt ofbitetrazole is 15 to 35% by weight, the content of (b) a basic coppernitrate is 30 to 70% by weight, the content of (c-1) sodium salt ofcarboxymethylcellulose is 0.1 to 15% by weight and the content of (c-2)is 1 to 45% by weight.

Still another preferable example of the composition comprisingcomponents (a), (b) and (c) is a composition comprising (a)nitroguanidine, (b) a basic copper nitrate and (c) sodiumcarboxymethylcellulose. In this case, it is preferable that the contentof (a) nitroguanidine is 15 to 55% by weight, the content of (b) a basiccopper nitrate is 45 to 70% by weight and the content of (c) sodium saltof carboxymethylcellulose is 0.1 to 15% by weight.

Other preferable example of the composition comprising components (a),(b) and (c) is a composition comprising (a) nitroguanidine, (b) a basiccopper nitrate, (c-1) sodium carboxymethylcellulose and (c-2) component(c) except for (c-1). In this case, it is preferable that the content of(a) nitroguanidine is 15 to 50% by weight, the content of (b) a basiccopper nitrate is 30 to 65% by weight, the content of (c-1) sodiumcarboxymethylcellulose is 0.1 to 15% by weight and the content of (c-2)is 1 to 40% by weight.

Other preferable example of the composition comprising components (a),(b) and (c) is a composition comprising (a) nitroguanidine, (b) a basiccopper nitrate and (c) guar gum. In this case, the content of (a)nitroguanidine is preferably 20 to 60% by weight, more preferably 30 to50% by weight, the content of (b) a basic copper nitrate is preferably35 to 75% by weight, more preferably 40 to 65% by weight, and thecontent of (c) guar gum is preferably 0.1 to 10% by weight, morepreferably 1 to 8% by weight.

Other preferable example of the composition comprising components (a),(b) and (c) is a composition comprising (a) nitroguanidine, (b) a basiccopper nitrate, (c-1) guar gum and (c-2) component (c) except for (c-1).In this case, the content of (a) nitroguanidine is preferably 20 to 60%by weight, more preferably 30 to 50% by weight, the content of (b) abasic copper nitrate is preferably 30 to 70% by weight, more preferably40 to 60% by weight, the content of (c-1) guar gum is preferably 0.1 to10% by weight, more preferably 2 to 8% by weight, and the content of(c-2) is preferably 0.1 to 10% by weight, more preferably 0.3 to 7% byweight.

The composition comprising (a) nitroguanidine and (b) a basic coppernitrate or the composition comprising (a) nitroguanidine, (b) a basiccopper nitrate and (c) guar gum provides effects in the following points(I) to (III).

(I) Since the thermal decomposition temperature of nitroguanidine(approximately 220° C.) is close to the thermal decompositiontemperature of a basic copper nitrate (approximately 200° C.), thereaction (combustion) of nitroguanidine and a basic copper nitrate iscloser to the complete combustion, and toxic gases (CO, NO, NO₂, NH₃ andthe like) are less generated. Further, since the use of a basic coppernitrate lowers the combustion temperature of the gas generating agent,the generated amount of so-called thermal NO_(x) is decreased.

(II) In the combustion, mist of molten copper is generated owing to abasic copper nitrate. However, since the melting point of copper (1,083°C.) is high, mist can easily be removed as solid mist by being cooled toapproximately 1,000° C. Thus, mist can easily be removed in comparisonwith other mist (for example, since the melting point of K₂O is 400° C.,the cooling to less than 400° C. is required), and mist is hardlydischarged outside the inflator.

(III) The use of guar gum provides a high thermal stability comparedwith the use of CMC—Na. In case of using CMC—Na, an OH ion generatedfrom a basic copper nitrate and Na of CMC—Na are reacted to form NaOH,and this NaOH sometimes decomposes nitroguanidine to decrease thethermal stability. However, guar gum does not pose such a problem.

Other preferable example of the composition comprising components (a),(b) and (c) is a composition comprising (a) dicyandiamide, (b) a basiccopper nitrate and (c) sodium salt of carboxymethylcellulose. In thiscase, it is preferable that the content of (a) dicyandiamide is 15 to25% by weight, the content of (b) a basic copper nitrate is 60 to 80% byweight and the content of (c) sodium salt of carboxymethylcellulose is0.1 to 20% by weight.

Other preferable example of the composition comprising components (a),(b) and (c) is a composition comprising (a) dicyandiamide, (b) a basiccopper nitrate, (c-1) sodium salt of carboxymethylcellulose and (c-2)component (c) except for (c-1). In this case, it is preferable that thecontent of (a) dicyandiamide is 15 to 25% by weight, the content of (b)a basic copper nitrate is 55 to 75% by weight, the content of (c-1)sodium salt of carboxymethylcellulose is 0 to 10% by weight or 0.1 to10% by weight and the content of (c-2) is 1 to 20% by weight.

Other preferable example of the composition comprising components (a),(b) and (c) is a composition comprising (a) guanidine nitrate, (b) abasic copper nitrate and (c) sodium salt of carboxymethylcellulose. Inthis case, it is preferable that the content of (a) guanidine nitrate is15 to 60% by weight, the content of (b) a basic copper nitrate is 40 to70% by weight and the content of (c) sodium salt ofcarboxymethylcellulose is 0.1 to 15% by weight.

Other preferable example of the composition comprising components (a),(b) and (c) is a composition comprising (a) guanidine nitrate, (b) abasic copper nitrate, (c-1) sodium salt of carboxymethylcellulose and(c-2) component (c) except for (c-1). In this case, it is preferablethat the content of (a) guanidine nitrate is 15 to 55% by weight, thecontent of (b) a basic copper nitrate is 25 to 60% by weight, thecontent of (c-1) sodium salt of carboxymethylcellulose is 0.1 to 15% byweight and the content of (c-2) is 1 to 40% by weight.

When component (b) is a mixture of a basic copper nitrate and potassiumnitrate in the gas generating composition of the invention, the effectof improving the burning rate is obtained in addition to the effects (I)to (III).

The gas generating composition of the invention can be a compositioncomprising (a), (b) and (d) a combustion-controlling agent(combustion-improving agent) as essential components or a compositioncomprising (a), (b), (c) and (d) a combustion-controlling agent(combustion-improving agent) The guanidine derivatives as component (a)when component (d) is contained as an essential component are guanidinederivatives of the second group.

The combustion-improving agent as component (d) is a component that actsto improve combustion properties such as a burning rate, a duration ofcombustion, an ignitability and the like of the overall gas generatingcomposition. As the combustion-improving agent, at least one selectedfrom the group consisting of silicon nitride, silica, a nitrite, anitrate, a chlorate or a perchlorate of an alkali metal or an alkalineearth metal (KNO₃, NaNO₃, KClO₄ or the like), iron (III) hydroxide oxide[FeO(OH)], copper oxide, iron oxide, zinc oxide, cobalt oxide andmanganese oxide is proposed. When iron (III) hydroxide oxide [FeO(OH)]of these is used, the combustion-accelerating effect of the binder isexcellent when a binder having a large number of carbon atoms isincorporated, and this can contribute to accelerating the combustion ofthe overall gas generating composition.

The content of component (d) is preferably 1 to 10 parts by weight, morepreferably 1 to 5 parts by weight per 100 parts by weight in total ofcomponents (a) and (b), or components (a), (b) and (c)

A preferable example of the composition comprising components (a), (b),(c) and (d) is a composition comprising (a) nitroguanidine, (b) a basiccopper nitrate, (c) guar gum and (d) the combustion-improving agent. As(d) the combustion-improving agent, silica is preferable. In this case,it is preferable that the content of (a) nitroguanidine is 20 to 60% byweight, the content of (b) a basic copper nitrate is 35 to 75% byweight, the content of (c) guar gum is 0.1 to 10% by weight and thecontent of (d) the combustion-improving agent is 0.1 to 15% by weight.

Further, the gas generating composition of the invention comprisescomponents (a) and (b), and can meet one requirement selected from thefollowing (1) to (3), preferably two requirements, more preferably threerequirements. In this case, the guanidine derivatives as component (a)are guanidine derivatives of the second group.

(1) A weight loss ratio of the gas generating agent when the gasgenerating composition is retained in a closed state at 90° C. for 1,000hours or at 110° C. for 400 hours is 2.0% or less, preferably 1.0% orless, more preferably 0.5% or less.

This requirement (1) is a weight loss ratio of the gas generatingcomposition when the gas generating composition is charged in astainless steel container having an inner capacity of 118.8 ml andretained in a closed state at 90° C. for 1,000 hours or at 110° C. for400 hours.

(2) Concentrations of trace gases contained in a gas generated by thecombustion of the gas generating composition, as values measured in a2,800-liter tank, 400 ppm or less for CO, 40 ppm or less for NO, 8 ppmor less for NO₂ and 100 ppm or less for NH₃.

This requirement (2) is that regarding concentrations of trace gasescontained in a gas generated by the combustion of the gas generatingcomposition, as values measured in a 2,800-liter tank, 400 ppm or lessfor CO, 40 ppm or less for NO, 8 ppm or less for NO₂ and 100 ppm or lessfor NH₃. Alternatively, they can be approximately 30%, preferably 30% orless, more preferably 20% or less, further preferably 10% (CO=120 ppm,NO=10 ppm, NO₂=2 ppm, NH₃=30 ppm) or less of IDLH values shown by NIOSHsuch that CO is 1,200 ppm or less, NO is 100 ppm or less, NO₂ is 20 ppmor less and NH₃ is 300 ppm or less.

Incidentally, these gas concentrations are, for example, values givenwhen a test of a 2,800-liter tank is conducted under conditions of 20°C. and an output of 130 to 230 kPa using a standard single-typepyrotechnic inflator for a driver side. This gas generating compositioncan be used in another type of a gas generator regardless of themeasuring conditions.

(3) A maximum internal pressure in a gas generator in the combustion ofthe gas generating composition is 7,840 to 22,500 kPa, preferably 8,820to 17,640 kPa.

Further, the gas generating composition of the invention comprisescomponents (a), (b) and (c), and can meet one requirement selected fromthe following (1) to (3), preferably two requirements, more preferablythree requirements. The details of requirements (1) to (3) are the sameas described above. In this case, the guanidine derivatives as component(a) are guanidine derivatives of the second group.

(1) A weight loss ratio of the gas generating agent when the gasgenerating composition is retained in a closed state at 90° C. for 1,000hours or at 110° C. for 400 hours is 2.0% or less.

(2) Concentrations of trace gases contained in a gas generated by thecombustion of the gas generating composition, as values measured in a2,800-liter tank, 400 ppm or less for CO, 40 ppm or less for NO, 8 ppmor less for NO₂ and 100 ppm or less for NH₃.

(3) A maximum internal pressure in a gas generator in the combustion ofthe gas generating agent is 7,840 to 22,500 kPa.

When the gas generating composition of the invention is a compositioncomprising components (a), (b) and (d) as essential components or acomposition comprising components (a), (b), (c) and (d), component (d)is not a component that inhibits the development of requirements (1) to(3). Thus, it meets requirements (1) to (3) like the composition free ofcomponent (d).

The gas generating composition of the invention can be molded in adesired shape, and formed into a molded article in the shape of asingle-perforated cylinder, a perforated (porous) cylinder or pellets.These molded articles can be produced by a method in which the gasgenerating composition is mixed with water or an organic solvent and themixture is extrusion-molded (molded articles in the form of asingle-perforated cylinder and a perforated (porous) cylinder) or by acompression-molding method using a pelletizer (molded article in theform of pellets).

The gas generating composition of the invention can be used in, forexample, an inflator for an air bag of a driver side, an inflator for anair bag of a passenger side, an inflator for a side air bag, an inflatorfor an inflatable curtain, an inflator for a knee bolster, an inflatorfor an inflatable seat belt, an inflator for a tubular system and a gasgenerator for a pretensioner in various vehicles.

Further, the gas generator using the gas generating composition of theinvention or the molded article obtained therefrom may be a pyrotechnictype in which a gas is supplied only from a gas generating agent aloneor a hybrid type in which a gas is supplied from both of a compressedgas such as argon or the like and a gas generating agent.

Moreover, the gas generating composition or the molded article obtainedtherefrom in the invention can also be used as an igniting agent calledan enhancer (or a booster) for transferring energy of a detonator or asquib to a gas generating agent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a scanning electron micrograph (×10,000) of a basic coppernitrate obtained in Example 5.

FIG. 2 is a scanning electron micrograph (×10,000) of a basic coppernitrate obtained in Example 5.

FIG. 3 is a scanning electron micrograph (×500) of a basic coppernitrate obtained in Example 5.

FIG. 4 is a scanning electron micrograph (×2,000) of a basic coppernitrate obtained in Example 5.

FIG. 5 is a scanning electron micrograph (×500) of a basic coppernitrate obtained in Example 7.

FIG. 6 is a scanning electron micrograph (×2,000) of a basic coppernitrate obtained in Example 7.

FIG. 7 is a scanning electron micrograph (×5,000) of a basic coppernitrate obtained in Example 7.

EXAMPLES

The invention is illustrated more specifically by referring to thefollowing Examples. However, the invention is not limited thereto.

(1) Identification of a Particle Diameter and a Particle Form (Whetheror not it is in the Form of Coagulated Particles)

A sample powder was fixed on an exclusive sample base. A particlediameter of the sample powder in visual images for observation of ×500,×2,000 and ×10,000 was measured using a scanning electron microscope,and a particle form was estimated at the same time. The particlediameter of principal particles when particles were (coagulated)secondary particles was likewise measured after secondary particles werecrushed into principal particles. Incidentally, when particles wereparticles in the form of needles, a length was defined as a particlediameter. When particles were particles in the form of plates, a maximumdiagonal length was defined as a particle diameter. Further, whenparticles were particles in the form of shapes similar to spheres, amajor axis was defined as a particle diameter.

(2) Specific Surface Area

Measured by the BET method using a nitrogen gas.

(3) Bulk Density

A measuring cylinder filled with 10 ml of a sample powder was put on ahorizontal base, and the horizontal base was tapped with the cylinder 30times. Then, a bulk density was measured.

(4) Measurement of a Degree of Crystallization (Half Band Width)

A half band width was measured from a main peak obtained by the powderX-ray diffraction method (Rietvelt method).

(5) Measurement of TG-DTA (Thermogravimetric-Differential ThermalAnalysis)

Conducted at a Rate of Temperature Rise of 20/min.

(6) Impurity Content (Based on Na Atom)

Measured by atomic absorption spectrometry.

(7) Thermal Stability

5 g of a basic metal nitrate such as a basic copper nitrate or the likewas charged into water, and heat-treated at 80° C. for 10 minutes. Atthis time, a change in appearance was measured. A product having a poorthermal stability turned black by this heat treatment.

(8) Thermal Stability Test (Weight Loss Ratio)

A gas generating composition (containing 40 g of a gas generating agent)was charged into an aluminum container to measure a total weight. (Totalweight—weight of an aluminum container) was defined as a weight of asample before the test. The aluminum container filled with the samplewas placed in an SUS thick container (inner capacity 118.8 ml), andcovered. This was put in a thermostat bath of 110° C. At this time, thecontainer was rendered in a sealed state using a rubber packing and aclamp. After the lapse of a predetermined period of time, the SUS thickcontainer was withdrawn from the thermostat bath. When the container wasreturned to room temperature, the container was opened, and the aluminumcontainer was withdrawn therefrom. The total weight of the sampleinclusive of the aluminum container was measured, and (totalweight—weight of an aluminum container) was defined as a weight of thesample after the test. And, the change in weight was measured bycomparing the weight before the test with that after the test to find aweight loss ratio, whereby the thermal stability was evaluated. Theweight loss ratio was calculated from [(weight of a gas generating agentbefore test—weight of a gas generating agent after test)/weight of a gasgenerating agent before test]×100.

Comparative Example 1

241.6 g (1.00 mol) of copper nitrate 3-hydrate was charged in a beakerfitted with a stirrer, and then dissolved in 500 ml of distilled waterwhich was poured therein, while being stirred. The resulting solutionwas heated at 60° C. A solution of 84.15 g (1.50 mols) of potassiumhydroxide in 500 ml of distilled water was added dropwise over 1 hourwhile being stirred. After the addition of the potassium hydroxideaqueous solution was completed, the mixture was stirred at 60° C. for 30minutes. The resulting gel-like precipitate was filtered at roomtemperature, and washed with distilled water. A basic copper nitrateobtained was a pale blue solid matter. The solid matter partiallycontained a gray material, and the filterability was bad. When a part ofthe washed product was dried in air at 110° C., the product turned blackas a whole, decomposition was observed in the drying step, and thethermal stability was quite bad. The remaining washed product was driedat 110° C. under reduced pressure of 1,333.22 Pa (10 mmHg) to obtain abasic metal nitrate. The results of measurements are shown in Table 1.

Example 1

36.3 g of copper nitrate 3-hydrate was charged in a beaker fitted with astirrer, and then dissolved in 100 ml of distilled water which waspoured therein, while being stirred. The resulting solution was heatedat 60° C. A solution of 18.9 g of sodium bicarbonate in 240 ml of waterwas added over 1 hour. After the addition was completed, the mixture wasaged while being stirred at 60° C. for 60 minutes. The resultinggel-like precipitate was filtered at room temperature, and washed withdistilled water. A pale blue solid matter having quite a goodfilterability was obtained. When a part of the washed product was driedin air at 110° C., the product maintained the pale blue color, and thethermal stability was quite good. The remaining washed product was driedat 110° C. under reduced pressure of 1,333.22 Pa to obtain a basiccopper nitrate in an amount of 17.4 g (yield 96.5%). The results ofmeasurements are shown in Table 1.

Example 2

36.3 g of copper nitrate 3-hydrate was charged in a beaker fitted with astirrer, and then dissolved in 100 ml of distilled water which waspoured therein, while being stirred. The resulting solution was heatedat 80° C. A solution of 18.9 g of sodium bicarbonate in 240 ml of waterwas added over 1 hour. Immediately after the addition was completed, aprecipitate was filtered, and washed with distilled water to obtain apale blue solid matter having quite a good filterability. When a part ofthe washed product was dried in air at 110° C., the product maintainedthe pale blue color, and the thermal stability was good. The remainingwashed product was dried at 110° C. under reduced pressure of 1,333.22Pa to obtain a basic copper nitrate. The results of measurements areshown in Table 1.

Example 3

214.6 g (1.00 mol) of copper nitrate 3-hydrate was charged in a beakerfitted with a stirrer, and then dissolved in 500 ml of distilled waterwhich was poured therein, while being stirred. The resulting solutionwas heated at 40° C. A solution of 126 g (1.50 mols) of sodiumbicarbonate in 1,000 ml of distilled water was added over 1 hour. Afterthe addition of sodium bicarbonate was completed, the mixture was heatedto 80° C., and aged for 30 minutes while being stirred. A precipitatewas filtered, washed, and dried to obtain a pale blue basic coppercarbonate. The results of measurements are shown in Table 1.

Example 4

A pale blue basic copper carbonate was obtained in the same manner as inExample 1 except that the amount of sodium bicarbonate was 21.4 g. Theresults of measurements are shown in Table 1.

Comparative Example 2

214.6 g (1.00 mol) of copper nitrate 3-hydrate was charged in a beakerfitted with a stirrer, and then dissolved in 1,000 ml of distilled waterwhich was poured therein, while being stirred. The resulting solutionwas heated at 95° C. 123.0 g (1.50 mols) of anhydrous sodium acetate wasthen added in small portions. After the addition of sodium acetate wascompleted, the mixture was further stirred for 30 minutes. The resultingprecipitate was filtered at room temperature, washed, and dried toobtain a pale blue solid matter in an amount of 84.7 g (yieldapproximately 70.5%). However, the yield was bad in comparison withExample 1. The results of measurements are shown in Table 1.

Example 5

36.3 g of copper nitrate 3-hydrate was charged in a beaker fitted with astirrer, and then dissolved in 20 ml of distilled water which was pouredtherein, while being stirred at room temperature (20° C.) to obtain asolution. A solution of 18.9 g of sodium bicarbonate in 240 ml of waterwas added dropwise at room temperature over 1.5 hours. After theaddition was completed, the mixture was aged at room temperature for 2hours while being stirred. The resulting precipitate was filtered,washed with distilled water until the filtrate was neutralized, anddried at 110° C. under reduced pressure of 1,333.22 Pa until a fixedweight was reached to obtain 16.0 g of a basic copper nitrate in theform of particles coagulated in the “chrysanthemum shape”. The resultsof measurements are shown in Table 2. By the way, the scanning electronmicrographs of a basic copper nitrate obtained in Example 5 are shown inFIG. 1 (×10,000), FIG. 2 (×10,000), FIG. 3 (×500) and FIG. 4 (×2,000).

Example 6

24.2 g of copper nitrate 3-hydrate was dissolved in 105 ml of water, anda solution of 12.6 g of sodium bicarbonate in 240 ml of water was addeddropwise at 60° C. over 1 hour with stirring. After the addition wascompleted, the mixture was aged at 60° C. over 1 hour while continuingthe stirring to form a precipitate. The resulting precipitate was washedwith pure water until the filtrate was neutralized, and dried in hot airat 110° C. until a fixed weight was reached. The results of measurementsare shown in Table 2.

Example 7

A solution of 90.5 g of copper nitrate in 50 g of water was continuouslyadded to 200 g of water adjusted to a pH of 3.8 with nitric acid over5.5 hours while the temperature was maintained at 5° C. During thistime, a solution of 47.5 g of sodium bicarbonate in 600 g of water wasadded to maintain the pH between 5.4 and 5.6. After the completion ofthe addition, the mixture was filtered, washed, and dried to obtain 39.7g of a basic copper nitrate. The results of measurements of theresulting basic copper nitrate are shown in Table 2, and the scanningelectron micrographs (×500, ×2,000 and ×5,000) are shown in FIGS. 5, 6and 7.

Example 8

44.2% by weight of nitroguanidine, 52.8% by weight of a basic coppernitrate in Example 5 and 3.0% by weight of guar gum were mixed to obtaina gas generating composition. The weight loss ratio of this compositionwas measured. Then, it was 0.12% when 94 hours passed, 0.25% when 234hours passed, and 0.36% when 405 hours passed.

The composition of the invention is illustrated more specifically byreferring to the following Examples. However, the invention is notlimited thereto. In the tables, NQ represents nitroguanidine, BHTNH₃represents ammonium salt of bitetrazole, BHTK represents potassiumbitetrazole, DCDA represents dicyandiamide, 5-AT represents5-aminotetrazole, Zn(5-AT) represents zinc salt of 5-aminotetrazole, BCNrepresents a basic copper nitrate [Cu₂(NO₃)(OH)₃], and CMCNa representssodium salt of carboxymethylcellulose. Incidentally, the measuringmethods are described in detail below.

(9) Thermal Stability Test (Weight Loss Ratio)

A gas generating composition (containing 40 g of a gas generating agent)was charged into an aluminum container to measure a total weight. (Totalweight—weight of an aluminum container) was defined as a weight of asample before the test. The aluminum container filled with the samplewas placed in an SUS thick container (inner capacity 118.8 ml), andcovered. At this time, the container was rendered in a sealed stateusing a rubber packing and a clamp. This was put in a thermostat bath of90° C. or 110° C. After the lapse of 1,000 hours and 400 hours, thecontainer was withdrawn from the thermostat bath. When the container wasreturned to room temperature, the container was opened, and the aluminumcontainer was withdrawn therefrom. The total weight of the sampleinclusive of the aluminum container was measured, and (totalweight—weight of an aluminum container) was defined as a weight of thesample after the test. And, the change in weight was measured bycomparing the weight before the test with that after the test to find aweight loss ratio, whereby the thermal stability was evaluated. Theweight loss ratio was calculated from [(weight of a gas generating agentbefore test—weight of a gas generating agent after test)/weight of a gasgenerating agent before test]×100.

(10) Measurement of a Gas Concentration

The closed container after the completion of the above thermal stabilitytest was put into a polyvinyl chloride bag filled with approximately 2liters of air, and the bag was then closed. A clamp was unfastened inthe bag to open the closed container, and the gas in the container wasreleased into the bag. The gas in the bag was diffused, and rendereduniform. Then, the detecting tube was pierced into the bag, and the gasconcentration was quickly measured.

(11) Measurement of an Internal Pressure

An internal pressure inside the container filled with the gas generatingcomposition after the thermal stability test was measured.

Examples 9 to 17 and Comparative Examples 3 and 4

Gas generating compositions each having a formulation shown in Table 3were produced. The combustion temperature, the gas output (unit “mol/100g” indicates the number of mols of the gas generated per 100 g of thecomposition) and the amounts of generated CO and NO of thesecompositions according to theoretical calculations are shown in Table 3.

It indicates that any combustion temperatures in Examples 9 to 17 arequite lower than those in Comparative Examples 3 and4 and less than1,900 K, and that the temperatures are effective for decreasing theamount of generated NO. Further, the amounts of generated CO and NO arenot permitted in practice unless the amount of generated CO being 2×10⁻³mol/100 g or less and the amount of generated NO being 2×10⁻⁴ mol/100 gor less are attained at the same time. It is found that these Examplessatisfy these conditions.

Examples 18 to 23

Gas generating compositions each having a formulation shown in Table 4were produced. These compositions were tested for a friction sensitivityand a drop hammer sensitivity according to the explosives performancetest method of JIS K 4810-1979. The results are shown in Table 4.

Examples 24 to 28

Gas generating compositions each having a formulation shown in Table 5were produced. With respect to these compositions, a melting temperaturewith a TAS-type differential thermal analyzer manufactured by Rigaku K.K., a temperature at which to start heating and a temperature at whichto start TG weight loss were measured. A rate of temperature rise in themeasurement was 20° C./min, a measurement atmosphere was a nitrogen gas,and an amount of a sample in the measurement was 1 to 2 mg. The resultsare shown in Table 5.

Further, with respect to the composition in Example 26, the thermalstability test was conducted by the following method. The thermalstability test was conducted by allowing an aluminum container filledwith the composition to stand in a thermostat bath of 110° C. for 400hours. The weight loss ratio was measured from the change in weight ofthe composition before and after the test, and the thermal stability wasevaluated. As a result, the weight loss ratio was as low as −0.31%, andno change in appearance was observed.

Examples 29 to 40

Gas generating compositions each having a formulation shown in Table 6were produced. Each of these compositions was molded into a strand. Aburning rate was measured in a nitrogen atmosphere at a pressure of4,900, 6,860 or 8,820 kPa. A burning rate at 6,860 kPa and a pressureindex of 4,900 to 8,820 kPa are shown in Table 6.

As stated above, the respective values shown in Examples 18 to 40 revealthat the compositions in these Examples meet the practical conditions asthe gas generating composition for the inflator.

Examples 41 to 63

Gas generating compositions each having a formulation shown in Table 7were produced. Each of the gas generating compositions was molded into 2g of a strand. This strand was installed in a closed bomb having aninner capacity of 1 liter, and the inside of the bomb was purged withnitrogen. Further, the bomb was pressurized to 6,860 kPa with nitrogen.The strand was ignited by electronic conduction through a nichrome wire,and completely burned. Approximately 20 seconds after the electronicconduction, the burned gas was collected in a gas sampling bag, and theconcentrations of NO₂, NO, CO and CO₂ were quickly analyzed with adetecting tube.

Examples 64 to 83

Gas generating compositions each having a formulation shown in Table 8were produced, and the concentrations of NO₂, NO, CO and CO₂ wereanalyzed as in Examples 41 to 63.

Examples 84 to 102

Gas generating compositions each having a formulation shown in Table 9were produced. A combustion temperature and a gas output (unit “mol/100g” indicates the number of mols of a generated gas per 100 g of thecomposition) of these compositions according to theoretical calculationsare shown in Table 9.

Example 103

A gas generating composition containing 44.2% by weight of NQ, 52.8% byweight of BCN and 3% by weight of guar gum was produced, and tested fora thermal stability by the following method. As a result, a weight lossratio under conditions of 110° C. and 214 hours was 0.27%, and a weightloss ratio under conditions of 110° C. and 408 hours was 0.45%.

Examples 104 to 111

Gas generating composition each having a formulation shown in Table 10was produced, and items shown in Table 10 were measured as in Examples 9to 103. TABLE 1 Temperature at which to start weight loss (° C.) Thermalstability Comparative 215 pale blue → black Example 1 Example 1 220 paleblue (no change in color) Example 2 pale blue (no change in color)Example 3 223 pale blue (no change in color) Example 4 pale blue (nochange in color) Comparative 219 pale blue → pale gray Example 2

TABLE 2 (c) (a) or (a-1) (a-2) (a-3) (b) Temperature (d) ParticleSpecific Bulk Degree of at which to Impurity diameter surface areadensity crystallinity start weight content Particle form (^(μ)m) (m²/g)(g/ml) (half bandwidth) loss (° C.) (ppm) Example 5 Coagulated 10-200.53 0.88 0.21 221 100 particles*¹ Example 6 Non-coagulated  3-15 3.50.40 0.34 220 — particles*² Example 7 Single crystal 0.5-3   — 0.45 — ——*¹Particles in Example 5 are secondary particles of coagulated principalparticles having a particle diameter of 3 to 6 ^(μ)m.*²Particles (non-coagulated) in Example 6 are amorphous plate crystalswith a maximum diagonal length of 3 to 15 ^(μ)m.

TABLE 3 Combustion Amount of CO Amount of NO Gas generating Compositionratio temperature Gas output generated generated composition (wt. %) (K)(mol/100 g) (mol/100 g) (mol/100 g) Example 9 BHTNH₃/BCN 28.75/71.251835 2.43 1.3 × 10⁻³ 7.7 × 10⁻⁵ Example 10 BHTK/BCN 44.52/55.48 18891.54 1.38 × 10⁻³  1.4 × 10⁻⁴ Example 11 BHTNH₃/BCN/CMCNa 24.9/72.1/3.01785 2.36 1.3 × 10⁻³ 7.7 × 10⁻⁵ Example 12 BHTNH₃/BCN/CMCNa22.33/72.67/5 1764 2.32 1.27 × 10⁻³  6.13 × 10⁻⁵  Example 13BHTNH₃/BCN/CMCNa 19.77/73.23/7 1743 2.28 1.2 × 10⁻³ 4.84 × 10⁻⁵  Example14 BHTNH₃/BCN/CMCNa/Fe₂O₃ 25.38/69.72/2.94/1.96 1732 2.38 1.7 × 10⁻³ 1.6× 10⁻⁵ Example 15 BHTNH₃/BCN/ 22.79/74.21/3 1770 2.28 1.2 × 10⁻³ 6.4 ×10⁻⁵ cellulose acetate Example 16 Zn (5-AT)₂/BCN 40/60 1878 2.04 — —Example 17 Zn (5-AT)₂/BCN/CMCNa 35/62/3 1819 2.03 — — ComparativeBHTK/KNO₃ 51.44/48.56 2393 1.26 5.1 × 10⁻⁴ 4.08 × 10⁻³  Example 3Comparative BHTNH₃/KNO₃/CMCNa 30.97/66.03/3.0 2099 2.15 3.0 × 10⁻³ 1.2 ×10⁻³ Example 4

TABLE 4 Friction Drop sensi- hammer Gas generating Composition tivitysensitivity composition ratio (wt. %) (kgf) (cm) Example 18 BHTNH₃/BCN28.75/71.25 >36.0 >100 Example 19 BHTK/BCN 44.52/55.48 >36.0 70-80Example 20 BHTNH₃/ 25.89/71.11/3 >36.0 >80 BCN/CMCNa Example 21NQ/BCN/CMCNa 32/60/8 >36.0 >50 Example 22 NQ/BCN/ 44.2/52.8/3 >36.060-70 guar gum Example 23 NQ/BCN/ 45.0/47.0/3/5 >36.0 >100 guar gum/KNO₃

TABLE 5 Temperature at which to start thermal Temperature at Gasgenerating Composition ratio Melting decomposition which to start TGcomposition (wt. %) temperature (° C) (° C.) weight loss (° C.) Example24 BHTNH₃/BCN 28.75/71.25 208 230 216 Example 25 BHTK/BCN 44.52/55.48198 362 201 Example 26 NQ/BCN/CMCNa 32/60/8 — 216.6 209.5 Example 27NQ/BCN/CMCNa 43.9/53.1/3 — 221.5 204.8 Example 28 Zn (5-AT)₂/BCN 40/60 —221.3 221.3

TABLE 6 Burning Pres- Gas generating Composition rate sure compositionratio (wt. %) (mm/sec) index Example 29 BHTNH₃/BCN 28.75/71.25 14.480.16 Example 30 BHTK/BCN 44.52/55.48 27.92 0.20 Example 31 BHTNH₃/25.89/71.11/3 14.99 0.15 BCN/CMCNa Example 32 NQ/BCN/CMCNa 28/64/8 7.90.33 Example 33 NQ/BCN/CMCNa 30/62/8 8.9 0.29 Example 34 NQ/BCN/CMCNa32/60/8 9.7 0.44 Example 35 NQ/BCN/ 44.2/52.8/3 10.8 0.58 guar gumExample 36 NQ/BCN/ 44.3/52.2/3/0.5 11.0 0.53 guar gum/KNO₃ Example 37NQ/BCN/ 44.4/51.6/3/1 12.0 0.64 guar gum/KNO₃ Example 38 NQ/BCN/44.6/50.4/3/2 11.8 0.71 guar gum/KNO₃ Example 39 NQ/BCN/ 44.7/49.3/3/315.7 0.48 guar gum/KNO₃ Example 40 NQ/BCN/ 45.0/47.0/3/5 17.8 0.41 guargum/KNO₄

TABLE 7 Composition Formulation ratio (wt. %) NO₂ (ppm) NO (ppm) CO(ppm) CO₂ (ppm) Example 41 NQ/BCN/CMCNa 49.3/49.7/1 0 8 360 2200 Example42 NQ/BCN/CMCNa 47.1/50.9/2 0 12 320 2500 Example 43 NQ/BCN/CMCNa41.9/55.1/3 0 65 60 3000 Example 44 NQ/BCN/CMCNa 42.9/54.1/3 0 55 1102800 Example 45 NQ/BCN/CMCNa 43.9/53.1/3 0 17 250 2500 Example 46NQ/BCN/CMCNa 44.9/52.1/3 0 12 340 3000 Example 47 NQ/BCN/CMCNa/Al(OH)₃42.5/49.5/3/5 0 1 300 2600 Example 48 NQ/BCN/CMCNa/Al(OH)₃ 40/47/3/10 00 240 2300 Example 49 NQ/BCN/CMCNa/Al(OH)₃ 37.5/44.5/3/15 0 1 380 2100Example 50 NQ/BCN/CMCNa/Al(OH)₃ 35/42/3/20 0 3 160 2000 Example 51NQ/BCN/CMCNa/Co(OH)₂ 42.5/49.5/3/5 0 3 240 2600 Example 52NQ/BCN/CMCNa/Co(OH)₂ 40/47/3/10 0 0 180 2200 Example 53NQ/BCN/CMCNa/Co(OH)₂ 37.5/44.5/3/15 0 1 200 2200 Example 54NQ/BCN/CMCNa/Co(OH)₂ 35/42/3/20 0 1 180 2000 Example 55 NQ/BCN/CMCNa/42.5/49.5/3/5 0 0 290 2100 Japanese acid clay Example 56NQ/BCN/CMCNa/mica 42.5/49.5/3/5 0 0 290 2100 Example 57NQ/BCN/CMCNa/CaCO₃ 42.5/49.5/3/5 0 5 270 2200 Example 58NQ/BCN/CMCNa/Al₂O₃ 42.5/49.5/3/5 0 2 310 2900 Example 59NQ/BCN/CMCNa/SiO₂ 42.5/49.5/3/5 0 1 310 2100 Example 60 NQ/BCN/guar gum44.2/52.8/3 0 8 410 2500 Example 61 NQ/BCN/guar gum/KNO₃ 44.4/51.6/3/1 05 320 2000 Example 62 NQ/BCN/guar gum/KNO₃ 44.7/49.3/3/3 0 1 350 1900Example 63 NQ/BCN/guar gum/KNO₃ 45.0/47.0/3/5 0 3 320 2000

TABLE 8 Composition Formulation ratio (wt. %) NO₂ (ppm) NO (ppm) CO(ppm) CO₂ (ppm) Example 64 BHTNH₃/BCN/CMCNa 24.89/72.11/3 0 32 220 2200Example 65 BHTNH₃/BCN/CMCNa 25.89/71.11/3 0 12 330 2000 Example 66BHTNH₃/BCN/CMCNa 26.89/70.11/3 0 10 400 1950 Example 67BHTNH₃/BCN/CMCNa/Fe₂O₃ 23.61/68.39/3/5 0 22 240 2050 Example 68BHTNH₃/BCN/CMCNa/Fe₂O₃ 23.78/53.22/3/20 0 5 180 1100 Example 69BHTNH₃/BCN/CMCNa/CuO 24.00/53.00/3/20 0 19 280 1500 Example 70BHTNH₃/BCN/CMCNa/Co₃O₄ 24.78/67.22/3/5 0 10 200 1900 Example 71BHTNH₃/BCN/CMCNa/Co₃O₄ 24.75/62.25/3/10 0 6 220 1600 Example 72BHTNH₃/BCN/CMCNa/Co₃O₄ 23.51/53.49/3/20 0 2 210 1800 Example 73BHTNH₃/BCN/CMCNa/MnO₂ 26.87/60.13/3/10 0 8 360 1800 Example 74BHTNH₃/BCN/CMCNa/Co(OH)₂ 20.24/56.76/3/20 0 7 110 1800 Example 75BHTNH₃/BCN/CMCNa/Co(OH)₂ 23.24/53.76/3/20 0 2 190 1700 Example 76BHTNH₃/BCN/CMCNa/Al(OH)₃ 24.24/52.76/3/20 0 11 180 1900 Example 77BHTNH₃/BCN/CMCNa/Al(OH)₃ 25.12/61.88/3/10 0 4 190 1600 Example 78BHTNH₃/BCN/CMCNa/CaCO₃ 22.24/54.76/3/20 0 20 190 1700 Example 79BHTNH₃/BCN/HPC/Co(OH)₂ 23.13/55.87/1/20 0 5 130 1600 Example 80BHTNH₃/BCN/HPC/Al(OH)₃ 23.13/55.87/1/20 0 22 60 1700 Example 81BHTNH₃/BCN/CMCNa/CoCO₃ 22.24/54.76/3/20 0 1 200 2000 Example 82BHTNH₃/BCN/CMCNa/basic 22.24/54.76/3/20 0 3 200 1800 zinc carbonateExample 83 BHTNH₃/BCN/CMCNa/basic 24.80/52.20/3/20 0 12 220 2000 coppercarbonate

TABLE 9 Combus- tion Gas temper- output Composition ature (mol/Formulation ratio (wt. %) (K) 100 g) Example 84 NQ/BCN/guar gum44.2/52.8/3 2168 2.76 Example 85 NQ/BCN/guar gum 45.2/51.8/3 2156 2.80Example 86 NQ/BCN/guar gum 46.2/50.8/3 2145 2.84 Example 87 NQ/BCN/guargum 41.9/54.1/4 2131 2.72 Example 88 NQ/BCN/guar gum 42.8/53.2/4 21212.76 Example 89 NQ/BCN/guar gum 43.8/52.2/4 2110 2.80 Example 90NQ/BCN/guar gum 39.5/55.5/5 2096 2.69 Example 91 NQ/BCN/guar gum40.5/54.5/5 2084 2.73 Example 92 NQ/BCN/guar gum 41.5/53.5/5 2073 2.77Example 93 NQ/BCN/guar gum 37.1/56.9/6 2059 2.65 Example 94 NQ/BCN/guargum 38.1/55.9/6 2048 2.69 Example 95 NQ/BCN/guar gum 39.1/54.9/6 20362.73 Example 96 NQ/BCN/ 44.3/52.2/3/0.5 2167 2.76 guar gum/KNO₃ Example97 NQ/BCN/ 44.4/51.6/3/1 2165 2.76 guar gum/KNO₃ Example 98 NQ/BCN/44.5/51.0/3/1.5 2164 2.76 guar gum/KNO₃ Example 99 NQ/BCN/ 44.6/50.4/3/22163 2.76 guar gum/KNO₃ Example 100 NQ/BCN/ 44.7/49.3/3/3 2162 2.75 guargum/KNO₃ Example 101 NQ/BCN/ 44.9/48.1/3/4 2160 2.75 guar gum/KNO₃Example 102 NQ/BCN/ 45.0/47.0/3/5 2159 2.75 guar gum/KNO₃

TABLE 10 Amount of Amount of Formulation and Burning Combustion Heat CONO composition ratio rate Pressure tempera- content generated generated(wt. %) (mm/sec) index ture (k) Gas output (cal/g) (mol/100 g) (mol/100g) Ex. 104 NQ/BCN/guar gum/SiO₂ = 12.30 0.35 2156 2.73 698 0.04952.05E−4 43.7/52.3/3/1 Ex. 105 NQ/BCN/guar gum/SiO2 = 12.88 0.31 21452.70 693 0.0492 1.81E−4 43.2/51.8/3/2 Ex. 106 NQ/BCN/guar gum/SiO₂ =13.11 0.32 2136 2.66 687 0.0417 1.92E−4 42.7/51.3/3/3 Ex. 107NQ/BCN/guar gum/SiO₂ = 13.83 0.29 2122 2.65 681 0.0486 1.40E−442.2/50.8/3/4 Ex. 108 NQ/BCN/guar gum/SiO₂ = 13.61 0.31 2110 2.62 6760.0483 1.23E−4 41.7/50.3/3/5 Ex. 109 NQ/BCN/guar gum/SiO₂ = 13.68 0.222087 2.56 664 0.0477 7.23E−5 40.7/49.3/3/7 Ex. 110 NQ/BCN/guar gum/SiO₂= 14.45 0.23 2062 2.51 653 0.0495 6.78E−4 39.8/48.2/3/9 Ex. 111NQ/BCN/guar gum/SiO₂ = 13.71 0.22 2038 2.45 641 0.0489 5.12E−538.8/47.2/3/11

1. A gas generating composition comprising a basic metal nitrate meetingat least one requirement of the following (b) to (d): (b) a degree ofcrystallinity having 0.35 deg or less of a half band width of the peakin the X-ray diffraction; (c) an initiation temperature of weight lossbeing 220° C. or higher according to TG-DTA analysis; and (d) animpurity content of 1,000 ppm or less based on Na atom.
 2. The gasgenerating composition as claimed in claim 1, wherein the basic metalnitrate is a basic copper nitrate.
 3. A gas generating compositioncomprising a fuel and the basic metal nitrate as defined in claim
 1. 4.A gas generating composition comprising a fuel and a basic metalnitrate, the basic metal nitrate meeting at least one requirementselected from (a-2) or (a-3): (a-2) a specific surface area of particlesbeing 0.4 to 6.0 m²/g; (a-3) a bulk density of particles being 0.4 g/mlor more.
 5. The gas generating composition as claimed in claim 4,comprising a fuel and a basic metal nitrate, the basic metal nitratemeeting at least one requirement selected from (a-2) or (a-3) andfurther (b) to (d): (b) a degree of crystallinity having 0.35 deg orless of a half band width of the peak in the X-ray diffraction; (c) aninitiation temperature of weight loss being 220° C. or higher accordingto TG-DTA analysis; and (d) an impurity content of 1,000 ppm or lessbased on Na atom.
 6. A gas generating composition comprising a fuel anda basic metal nitrate, the basic metal nitrate being in the form ofsecondary particles of coagulated principal particles, the secondaryparticles meeting at least one requirement selected from (a-2) or (a-3):(a-2) a specific surface area of particles being 0.4 to 6.0 m²/g; (a-3)a bulk density of particles being 0.4 g/ml or more.
 7. The gasgenerating composition as claimed in claim 6, comprising a fuel and abasic metal nitrate, the basic metal nitrate meeting at least onerequirement selected from (a-2) or (a-3) and further the following (b)to (d): (b) a degree of crystallinity having 0.35 deg or less of a halfband width of the peak in the X-ray diffraction; (c) an initiationtemperature of weight loss being 220° C. or higher according to TG-DTAanalysis; and (d) an impurity content of 1,000 ppm or less based on Naatom.
 8. The gas generating composition as claimed in claim 6, whereinthe basic metal nitrate in the form of the secondary particles is formedby coagulating a large number of principal particles having the form ofneedles to plates and/or spheres to similar shapes thereto.
 9. The gasgenerating composition as claimed in claim 4, wherein the fuel is anitrogen-containing compound selected from the group consisting ofguanidine derivatives, azole derivatives, triazine derivatives andtransition metal complexes.
 10. The gas generating composition asclaimed in claim 9, wherein the fuel is nitroguanidine.
 11. The gasgenerating composition as claimed in claim 4, wherein the basic metalnitrate is a basic copper nitrate.
 12. The gas generating composition asclaimed in claim 4, which further comprises an additive.
 13. The gasgenerating composition as claimed in claim 12, wherein the additive isguar gum.
 14. The gas generating composition as claimed in claim 4,which has a weight loss ratio of 2.0% by weight or less when it isallowed to stand in an atmosphere of a temperature of 1100 for 400hours.
 15. The gas generating composition as claimed in claim 3, whereinsaid basic metal nitrate is a basic copper nitrate.
 16. A gas generatingcomposition comprising (a) tetrazole derivatives, guanidine derivativesor a mixture thereof, (b) a basic metal nitrate and (d) acombustion-improving agent.
 17. A gas generating composition comprising(a) tetrazole derivatives, guanidine derivatives or a mixture thereof,(b) a basic metal nitrate, (c) a binder and/or a slag-forming agent, and(d) a combustion-improving agent.
 18. The gas generating composition asclaimed in claim 16, wherein (d) the combustion-improving agent is atleast one selected from the group consisting of silicon nitride, silica,a nitrite, a nitrate, a chlorate or a perchlorate of an alkali metal oran alkaline earth metal (KNO₃, NaNO₃, KClO₄), iron (III) hydroxide oxide[FeO(OH)], copper oxide, iron oxide, zinc oxide, cobalt oxide andmanganese oxide.
 19. The gas generating composition as claimed in claim17, wherein (d) the combustion-improving agent is at least one selectedfrom the group consisting of silicon nitride, silica, a nitrite, anitrate, a chlorate or a perchlorate of an alkali metal or an alkalineearth metal (KNO₃, NaNO₃, KClO₄), iron (III) hydroxide oxide [FeO(OH)],copper oxide, iron oxide, zinc oxide, cobalt oxide and manganese oxide.20. A gas generating composition comprising (a) tetrazole derivatives,guanidine derivatives or a mixture thereof and (b) a basic metal nitrateand meeting at least one requirement selected from the following (1) to(3): (1) a weight loss ratio of the gas generating composition when thegas generating composition is retained in a closed state at 90° C. for1,000 hours or at 110° C. for 400 hours is 2.0% or less, (2)concentrations of trace gases contained in a gas generated by thecombustion of the gas generating composition, as values measured in a2,800-liter tank, 400 ppm or less for CO, 40 ppm or less for NO, 8 ppmor less for NO₂ and 100 ppm or less for NH₃, and (3) a maximum internalpressure in a gas generator on the combustion of the gas generatingcomposition is 7,840 to 22,500 kPa.
 21. A gas generating compositioncomprising (a) tetrazole derivatives, guanidine derivatives or a mixturethereof, (b) a basic metal nitrate and (c) a binder and/or aslag-forming agent and meeting at least one requirement selected fromthe following (1) to (3): (1) a weight loss ratio of the gas generatingcomposition when the gas generating composition is retained in a closedstate at 90° C. for 1,000 hours or at 110° C. for 400 hours is 2.0% orless, (2) concentrations of trace gases contained in a gas generated bythe combustion of the gas generating composition, as values measured ina 2,800-liter tank, 400 ppm or less for CO, 40 ppm or less for NO, 8 ppmor less for NO₂ and 100 ppm or less for NH₃, and (3) a maximum internalpressure in a gas generator on the combustion of the gas generatingcomposition is 7,840 to 22,500 kPa.
 22. The gas generating compositionas claimed in claim 16, wherein component (a) is a tetrazole derivativeselected from the group consisting of tetrazole, 5-aminotetrazole,5,5′-bi-1H-tetrazole, 5-nitroaminotetrazole, zinc salt of5-aminotetrazole, copper salt of 5-aminotetrazole, bitetrazole,potassium salt of bitetrazole, sodium salt of bitetrazole, magnesiumsalt of bitetrazole, calcium salt of bitetrazole, diammonium salt ofbitetrazole, copper salt of bitetrazole and melamine salt ofbitetrazole.
 23. The gas generating composition as claimed in claim 16,wherein component (a) is a guanidine derivative selected from the groupconsisting of guanidine, mono-, di- or tri-aminoguanidine nitrate,guanidine nitrate, guanidine carbonate, nitroguanidine, dicyandiamideand nitroaminoguanidine nitrate.
 24. The gas generating composition asclaimed in claim 16, wherein component (b) is a basic metal nitrateselected from the group consisting of a basic copper nitrate, a basiccobalt nitrate, a basic zinc nitrate, a basic manganese nitrate, a basiciron nitrate, a basic molybdenum nitrate, a basic bismuth nitrate and abasic cerium nitrate.
 25. The gas generating composition as claimed inclaim 24, wherein component (b) is a mixture of a basic metal nitrateand at least one other oxidizing agent.
 26. The gas generatingcomposition as claimed in claim 25, wherein component (b) is a mixtureof a basic metal nitrate and at least one other oxidizing agent whichincludes an alkali metal nitrate.
 27. The gas generating composition asclaimed in claim 26, wherein when component (b) is a mixture, the alkalimetal nitrate contained as at least one other oxidizing agent ispotassium nitrate.
 28. The gas generating composition as claimed inclaim 25, wherein the content of the basic metal nitrate in the mixtureis 55 to 99.9% by weight.
 29. The gas generating composition as claimedin claim 17, wherein the binder and/or the slag-forming agent ascomponent (c) is not crosslinkable and is at least one member selectedfrom the group consisting of polyacrylic amide, aminated compounds ofpolyacrylic amide, polyacrylic hydrazide, a copolymer of an acrylicamide and a metal salt of acrylic acid, a copolymer of polyacrylic amideand polyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum,starch, polysaccharides including starch, silicone, molybdenumdisulfide, Japanese acid clay, talc, bentonite, diatomaceous earth,kaolin, calcium stearate, silica, alumina, sodium silicate, siliconnitrate, silicon carbide, hydrotalcite, mica, a metal oxide, a metalhydroxide, a metal carbonate, a basic metal carbonate, and a molybdate.30. The gas generating composition as claimed in claim 29, whereincomponent (c) is a metal oxide selected from the group consisting ofcopper oxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide,molybdenum oxide, nickel oxide, and bismuth oxide, a metal hydroxideselected from the group consisting of cobalt hydroxide and aluminumhydroxide, a metal carbonate or a basic metal carbonate selected fromthe group consisting of calcium carbonate, cobalt carbonate, a basiczinc carbonate, and a basic copper carbonate, or a molybdate selectedfrom the group consisting of cobalt molybdate and ammonium molybdate.31. A gas generating composition which comprises (a) nitroguanidine, and(b) a basic copper nitrate.
 32. The gas generating composition asclaimed in claim 31, which comprises 30 to 70% by weight of (a)nitroguanidine and 30 to 70% by weight of (b) a basic copper nitrate.33. The gas generating composition as claimed in claim 31, whichcomprises (a) nitroguanidine, (b) a basic copper nitrate and (c) sodiumcarboxymethylcellulose.
 34. The gas generating composition as claimed inclaim 33, which comprises 15 to 55% by weight of (a) nitroguanidine, 45to 70% by weight of (b) a basic copper nitrate and 0.1 to 15% by weightof (C) sodium carboxymethylcellulose.
 35. The gas generating compositionas claimed in claim 31, which comprises (a) nitroguanidine, (b) a basiccopper nitrate, (c-1) sodium carboxymethylcellulose, and (c-2) a memberselected from the group consisting of polyacrylic amide, aminatedcompounds of polyacrylic amide, polyacrylic hydrazide, a copolymer of anacrylic amide and a metal salt of acrylic acid, a copolymer ofpolyacrylic amide and polyacrylic ester, polyvinyl alcohol, acrylicrubber, guar gum, starch, polysaccharides including starch, silicone,molybdenum disulfide, Japanese acid clay, talc, bentonite, diatomaceousearth, kaolin, calcium stearate, silica, alumina, sodium silicate,silicon nitrate, silicon carbide, hydrotalcite, mica, a metal oxide, ametal hydroxide, a metal carbonate, a basic metal carbonate, and amolybdate.
 36. The gas generating composition as claimed in claim 35,which comprises 15 to 50% by weight of (a) nitroguanidine, 30 to 65% byweight of (b) a basic copper nitrate, 0.1 to 15% by weight of (c-1)sodium carboxymethylcellulose and 1 to 40% by weight of (c-2).
 37. Thegas generating composition as claimed in claim 31, which comprises (a)nitroguanidine, (b) a basic copper nitrate, and (c) guar gum.
 38. Thegas generating composition as claimed in claim 37, which comprises 20 to60% by weight of (a) nitroguanidine, 35 to 75% by weight of (b) a basiccopper nitrate and 0.1 to 10% by weight of guar gum.
 39. The gasgenerating composition as claimed in claim 37, which comprises (a)nitroguanidine, (b) a basic copper nitrate, (c-1) guar gum, and (c-2) amember selected from the group consisting of polyacrylic amide, aminatedcompounds of polyacrylic amide, polyacrylic hydrazide, a copolymer of anacrylic amide and a metal salt of acrylic acid, a copolymer ofpolyacrylic amide and polyacrylic ester, polyvinyl alcohol, acrylicrubber, guar gum, starch, polysaccharides including starch, silicone,molybdenum disulfide, Japanese acid clay, talc, bentonite, diatomaceousearth, kaolin, calcium stearate, silica, alumina, sodium silicate,silicon nitrate, silicon carbide, hydrotalcite, mica, a metal oxide, ametal hydroxide, a metal carbonate, a basic metal carbonate, and amolybdate.
 40. The gas generating composition as claimed in claim 39,which comprises 20 to 60% by weight of (a) nitroguanidine, 30 to 70% byweight of (b) a basic copper nitrate, 0.1 to 10% by weight of (c-1) guargum, and 0.1 to 10% by weight of (c-2).
 41. The gas generatingcomposition as claimed in claim 17, which comprises (a) nitroguanidine,(b) a basic copper nitrate, (c) guar gum, and (d) a combustion-improvingagent.
 42. The gas generating composition as claimed in claim 41, whichcomprises 20 to 60% by weight of (a) nitroguanidine, 35 to 75% by weightof (b) a basic copper nitrate, 0.1 to 10% by weight of (c) guar gum and0.1 to 15% by weight of (d) a combustion-improving agent.
 43. The gasgenerating composition as claimed in claim 41, wherein (d) thecombustion-improving agent is silica.
 44. The gas generating compositionas claimed in claim 31, which comprises a mixture of a basic coppernitrate and potassium nitrate as component (b).
 45. A gas generatingcomposition which comprises (a) dicyandiamide and (b) a basic coppernitrate.
 46. The gas generating composition as claimed in claim 45,which comprises 15 to 30% by weight of (a) dicyandiamide and 70 to 85%by weight of (b) a basic copper nitrate.
 47. The gas generatingcomposition as claimed in claim 45, which comprises (a) dicyandiamide,(b) a basic copper nitrate, and (c) sodium carboxymethylcellulose. 48.The gas generating composition as claimed in claim 47, which comprises15 to 25% by weight of (a) dicyandiamide, 60 to 80% by weight of (b) abasic copper nitrate, and 0.1 to 20% by weight of (c) sodiumcarboxymethylcellulose.
 49. The gas generating composition as claimed inclaim 31, which comprises (a) dicyandiamide, (b) a basic copper nitrate,(c-1) sodium carboxymethylcellulose, and (c-2) a member selected fromthe group consisting of polyacrylic amide, aminated compounds ofpolyacrylic amide, polyacrylic hydrazide, a copolymer of an acrylicamide and a metal salt of acrylic acid, a copolymer of polyacrylic amideand polyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum,starch, polysaccharides including starch, silicone, molybdenumdisulfide, Japanese acid clay, talc, bentonite, diatomaceous earth,kaolin, calcium stearate, silica, alumina, sodium silicate, siliconnitrate, silicon carbide, hydrotalcite, mica, a metal oxide, a metalhydroxide, a metal carbonate, a basic metal carbonate, and a molybdate.50. The gas generating composition as claimed in claim 49, whichcomprises 15 to 25% by weight of (a) dicyandiamide, 55 to 75% by weightof (b) a basic copper nitrate, 0 to 10% by weight of (c-1) sodiumcarboxymethylcellulose, and 1 to 20% by weight of (c-2).
 51. The gasgenerating composition as claimed in claim 45, which comprises a mixtureof a basic copper nitrate and potassium nitrate as component (b).
 52. Agas generating composition comprising (a) guanidine nitrate, (b) a basiccopper nitrate, and (c) sodium carboxymethylcellulose.
 53. The gasgenerating composition as claimed in claim 52, which comprises 15 to 60%by weight of (a) guanidine nitrate, 40 to 70% by weight of (b) a basiccopper nitrate, and 0.1 to 15% by weight of (c) sodiumcarboxymethylcellulose.
 54. A gas generating composition comprising (a)guanidine nitrate, (b) a basic copper nitrate, (c-1) sodiumcarboxymethylcellulose, and (c-2) a member selected from the groupconsisting of polyacrylic amide, aminated compounds of polyacrylicamide, polyacrylic hydrazide, a copolymer of an acrylic amide and ametal salt of acrylic acid, a copolymer of polyacrylic amide andpolyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum, starch,polysaccharides including starch, silicone, molybdenum disulfide,Japanese acid clay, talc, bentonite, diatomaceous earth, kaolin, calciumstearate, silica, alumina, sodium silicate, silicon nitrate, siliconcarbide, hydrotalcite, mica, a metal oxide, a metal hydroxide, a metalcarbonate, a basic metal carbonate, and a molybdate.
 55. The gasgenerating composition as claimed in claim 54, which comprises 15 to 55%by weight of (a) guanidine nitrate, 25 to 60% by weight of (b) a basiccopper nitrate, 0.1 to 15% by weight of (c-1) sodiumcarboxymethylcellulose, and 1 to 40% by weight of (c-2).
 56. The gasgenerating composition as claimed in claim 52, which comprises a mixtureof a basic copper nitrate and potassium nitrate as component (b).
 57. Amolded article in the form of a single-perforated cylinder, a perforated(porous) cylinder or pellets, the molded article being obtained from thegas generating composition as claimed in claim
 1. 58. An inflator for anair bag using the gas generating composition as claimed in claim
 1. 59.An inflator for an air bag using the molded article as claimed in claim57.